What are WERf973.dir00 files?

I have about 13 files of the type WERf973.dir00 on my computer. These files take up an extraordinary amount of space (about 250 M), which is a real pain when I make an image of my C: drive.They seem to be from DOpus.
Are they needed?
Can I delete them?
Can they be stopped from re-appearing?

I don't think they're anything to do with Opus.

I believe WER = Windows Error Reporting and these are dumps indicating that there is a problem on your system. Have a look at this thread on LockerGnome for further insight.

Regards, AB

Thanks for that. For the life of me I can't recall where these files were, but Windows search cannot now find them, so they are gone.