楼主最好把提示贴出来，便于分析是什么的问题。

不然可能性也太多了

我的是并口连接,我已经检查过电缆,也试过将并口设置为旧式即插即用型,也是出现下面这问题

Welcome to iMPACT! - The intelligent Multi-purpose Programming And Configuration Tool
AutoDetecting cable. Please wait.
CB_PROGRESS_START - Starting Operation.
Connecting to cable (USB Port).
Cable connection failed.
Connecting to cable (Parallel Port - LPT1).
Connecting to cable (Parallel Port - LPT2).
Connecting to cable (Parallel Port - LPT3).
Connecting to cable (COM1 Port).
Cable connection failed.
Connecting to cable (COM2 Port).
Cable connection failed.
Connecting to cable (COM3 Port).
Cable connection failed.
Connecting to cable (COM4 Port).
Cable connection failed.
Elapsed time = 25 sec.
Cable autodetection failed.
'1': Loading file 'xtest1.bit' ...
done.

还有这个ModelSim 6.0是怎么一回事,老是报错

Updating: Generate Expected Simulation Results

Starting: 'exewrap -tapkeep -mode pipe -sen 50 -tcl -command C:/Xilinx/data/projnav/__simulateAnnoTestBench.tcl __antTOano.rsp'
Creating TCL Process
Running Automatic Do File: counter_tbw.ado
Starting: '@HKLM/SOFTWARE/Classes/XLNXEDA/products/DESIGNCNTR10/paths/VSystemPath/@/vsim -c -do counter_tbw.ado'
fatal error(0002): The system cannot find the file specified.

Tcl Unable to run the process due to a system error.

VSim failed to simulate annotated testbench
Reason:
Done: failed with exit code: 0002.

连接的问题和例子没有任何关系，这是一个硬件问题，只和下载电缆及其设置有关系，另外检查一下你板子上送给下载线的电源是否正确。

那么仿真是怎么一回事，老报错

在xilinx专区有一个置顶的帖子，是关于modelsim的，你可以看看。