Problem with "first" example,

Hi,

I have tried my best to solve this problem, but it did not work.
I added the “first.v” into a new project and add those ngc files into my project directories. The project can synthesize, but I get some warnings when runing implement design and errors when generating programming files. I show these warnings and errors below, can anyone know these problems and help me solve it. thanks a lot.
PS: my ISE version is 14.2 and OS is windows 10.

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warnings when implementing design:

WARNING:NgdBuild:578 - Design contains no instances.
Gathering constraint information from source properties…
Done.

Annotating constraints to design from ucf file “first.ucf” …
Resolving constraint associations…
Checking Constraint Associations…
WARNING:ConstraintSystem:137 - Constraint <NET “hi_in<0>” TNM_NET =
“okHostClk”;> [first.ucf(48)]: No appropriate instances for the TNM
constraint are driven by “hi_in<0>”.

WARNING:ConstraintSystem:56 - Constraint <TIMESPEC “TS_okHostClk” = PERIOD
“okHostClk” 20.83 ns HIGH 50%;> [first.ucf(49)]: Unable to find an active
‘TNM’ or ‘TimeGrp’ constraint named ‘okHostClk’.

WARNING:ConstraintSystem:191 - The TNM ‘okHostClk’, does not directly or
indirectly drive any flip-flops, latches and/or RAMS and cannot be actively
used by the referencing Period constraint ‘TS_okHostClk’. If clock manager
blocks are directly or indirectly driven, a new TNM constraint will not be
derived even though the referencing constraint is a PERIOD constraint unless
an output of the clock manager drives flip-flops, latches or RAMs. This TNM
is used in the following user PERIOD specification:
<TIMESPEC “TS_okHostClk” = PERIOD “okHostClk” 20.83 ns HIGH 50%;>
[first.ucf(49)]

WARNING:ConstraintSystem:197 - The following specification is invalid because
the referenced TNM constraint was removed:
<TIMESPEC “TS_okHostClk” = PERIOD “okHostClk” 20.83 ns HIGH 50%;>
[first.ucf(49)]

Done…

Checking expanded design …
WARNING:NgdBuild:470 - bidirect pad net ‘hi_inout<15>’ has no legal driver
WARNING:NgdBuild:470 - bidirect pad net ‘hi_inout<14>’ has no legal driver
WARNING:NgdBuild:470 - bidirect pad net ‘hi_inout<13>’ has no legal driver
WARNING:NgdBuild:470 - bidirect pad net ‘hi_inout<12>’ has no legal driver
WARNING:NgdBuild:470 - bidirect pad net ‘hi_inout<11>’ has no legal driver
WARNING:NgdBuild:470 - bidirect pad net ‘hi_inout<10>’ has no legal driver
WARNING:NgdBuild:470 - bidirect pad net ‘hi_inout<9>’ has no legal driver
WARNING:NgdBuild:470 - bidirect pad net ‘hi_inout<8>’ has no legal driver
WARNING:NgdBuild:470 - bidirect pad net ‘hi_inout<7>’ has no legal driver
WARNING:NgdBuild:470 - bidirect pad net ‘hi_inout<6>’ has no legal driver
WARNING:NgdBuild:470 - bidirect pad net ‘hi_inout<5>’ has no legal driver
WARNING:NgdBuild:470 - bidirect pad net ‘hi_inout<4>’ has no legal driver
WARNING:NgdBuild:470 - bidirect pad net ‘hi_inout<3>’ has no legal driver
WARNING:NgdBuild:470 - bidirect pad net ‘hi_inout<2>’ has no legal driver
WARNING:NgdBuild:470 - bidirect pad net ‘hi_inout<1>’ has no legal driver
WARNING:NgdBuild:470 - bidirect pad net ‘hi_inout<0>’ has no legal driver
WARNING:NgdBuild:470 - bidirect pad net ‘hi_aa’ has no legal driver

============================================================
errors when generating programming files:

ERROR:PhysDesignRules:368 - The signal <hi_muxsel_OBUF> is incomplete. The
signal is not driven by any source pin in the design.
ERROR:PhysDesignRules:368 - The signal <i2c_sda_OBUF> is incomplete. The signal
is not driven by any source pin in the design.
ERROR:PhysDesignRules:368 - The signal <led<0>_OBUF> is incomplete. The signal
is not driven by any source pin in the design.
ERROR:PhysDesignRules:368 - The signal <led<1>_OBUF> is incomplete. The signal
is not driven by any source pin in the design.
ERROR:PhysDesignRules:368 - The signal <led<2>_OBUF> is incomplete. The signal
is not driven by any source pin in the design.
ERROR:PhysDesignRules:368 - The signal <led<3>_OBUF> is incomplete. The signal
is not driven by any source pin in the design.
ERROR:PhysDesignRules:368 - The signal <led<4>_OBUF> is incomplete. The signal
is not driven by any source pin in the design.
ERROR:PhysDesignRules:368 - The signal <i2c_scl_OBUF> is incomplete. The signal
is not driven by any source pin in the design.
ERROR:PhysDesignRules:368 - The signal <led<5>_OBUF> is incomplete. The signal
is not driven by any source pin in the design.
ERROR:PhysDesignRules:368 - The signal <led<6>_OBUF> is incomplete. The signal
is not driven by any source pin in the design.
ERROR:PhysDesignRules:368 - The signal <led<7>_OBUF> is incomplete. The signal
is not driven by any source pin in the design.
ERROR:PhysDesignRules:368 - The signal <hi_out<0>_OBUF> is incomplete. The
signal is not driven by any source pin in the design.
ERROR:PhysDesignRules:368 - The signal <hi_out<1>_OBUF> is incomplete. The
signal is not driven by any source pin in the design.
ERROR:PhysDesignRules:10 - The network <hi_muxsel_OBUF> is completely unrouted.
ERROR:PhysDesignRules:10 - The network <i2c_sda_OBUF> is completely unrouted.
ERROR:PhysDesignRules:10 - The network <led<0>_OBUF> is completely unrouted.
ERROR:PhysDesignRules:10 - The network <led<1>_OBUF> is completely unrouted.
ERROR:PhysDesignRules:10 - The network <led<2>_OBUF> is completely unrouted.
ERROR:PhysDesignRules:10 - The network <led<3>_OBUF> is completely unrouted.
ERROR:PhysDesignRules:10 - The network <led<4>_OBUF> is completely unrouted.
ERROR:PhysDesignRules:10 - The network <i2c_scl_OBUF> is completely unrouted.
ERROR:PhysDesignRules:10 - The network <led<5>_OBUF> is completely unrouted.
ERROR:PhysDesignRules:10 - The network <led<6>_OBUF> is completely unrouted.
ERROR:PhysDesignRules:10 - The network <led<7>_OBUF> is completely unrouted.
ERROR:PhysDesignRules:10 - The network <hi_out<0>_OBUF> is completely unrouted.
ERROR:PhysDesignRules:10 - The network <hi_out<1>_OBUF> is completely unrouted.
ERROR:Bitgen:25 - DRC detected 26 errors and 2 warnings. Please see the
previously displayed individual error or warning messages for more details.