I'm having the same problem. Initially in my local file I was using tunneling (using a filemaker data source) to look up customer ID info because I already had the info in another file. Then I saw other posts that said that IWP had issues with multi-file sourcing, so I created a new table to reflect the information I was getting from the other file, but IWP still won't show any information after the pop-up option is selected and submitted. It just goes blank.
Any suggestions?? I'd really appreciate it!!