Er, sorry I wasn't clear. Technical terms aren't my strong suit, so I'll describe what I was doing in more detail, in the hopes that it answers that question.
I was running the regular weidu installer, using the setup-xxx.tp2 to install a mod that contained errors, like missing tildes, missing END's at the end of APPEND's, that kind of thing. Setup-xxx.tp2 was working just fine. It was the files that had bad code. I'd get the error message like I should, would select "quit" to stop the installation, hit ENTER to exit, the command window would close, I'd go fix the files that were messed up, and restart the installer. When the installer didn't hit any errors in the files it was compiling, the weidu.lock was deleted as I expected it to be, but if I did have errors severe enough to stop the installation, the weidu.lock remained after hitting ENTER to close the command window.