I think I understand the problem. When Lines View is not selected when Compare it! is started there is no problem. You can select it and deselect it as many times as possible without giving an error.
But when Lines View is selected and you deselect and select again then it crashes. Even in the hyperlink that you send. I hope that I discribed the problem correctly.
Try the two options and you will see what I mean.
P.S. did you added PDF to the converters?? I think I am the first one to test this function.
As for pdf, yes, but it would need additional conversion dll. You can get it there: http://www.grigsoft.com/cnv/pdftotext.zip. Just place to the same folder where wincmp3.exe is.