Does the script fail during Load Test or Validation? Sounds like you went right to Load Test. Unfortunately, DO_WSK_Expect() is the only error checking that is supported within Winsock middleware which is not powerful to begin with.
Maybe if I give an idea about how DO_Expect works it could give you some direction. DO_WSK_Expect starts at the END of the response string and works its way backwards until it find a unique pattern. I would go back to Workbench and try to Validate the script first. What I would do is the following:
Try to run your capture twice (with or without the datapools) each one seperately. Than go back to workbench and compare them, pay attention specifically to the Expects() to see that maybe they're generated in some UNIQUE way which will of course cause the TIMEOUT.
There is a runtime log generated while validation or even when running the scripts through the conductor (you need to select logging option )that would tell you a lot more as to what was ACTUALLY received against that expect. I would start there.
pszPointer - a string pointer - will contain the entire reply buffer, converted into the ususal Winsock script (null characters converted to ^@, for example). This will let you double check what is happening.
However, it sounds like the message you received is "Timed Out Validating" - if this is the case, it is likely that two things are happening: First, you are not replaying the script accurately, as the WSK_Expects should all work properly - if you search the log file you will see the word TIMEOUT in it. This is bad, and you'll need to investigate why the server is sending something different back to you.
The other option which will immediately fix this problem is to select Options->Workbench and click on the Validate Tab, and change the Validate timeout from the default of 50 seconds to something higher. However, unless you have a transaction that actually takes longer than 20 seconds (the default Winsock Script timeout option), this only masks the problem.