Let me know what the project number is, the ST-blahblah bit, and if you can also include any Error Tracker numbers (if you get the Cryptic Error window when a crash occurs the Error Tracker number will be listed under the white comment box) and I'll see what I can find out.
That crash is associated with the costume import/export functions in the Foundry. The good news is that it is assigned to a programmer. The bad news is that it may be a while before a fix can be found. I know it sucks but I have to ask that you please be patient.
That "Text must be filled in." that doesn't point to the spot is a bug I've been hunting for a while. I had it happen once but couldn't reproduce the issue.
The inability to delete the mission is an issue we had occuring before on Tribble but there was a fix for that. So, this needs further investigation as well.
I'm going to see if I can get a copy of your mission and investigate some more.
Again, I know this kind of thing is frustrating but please be patient.