At a guess, from things I've read in the past, I'd say you've got a corrupt file somewhere and from the info you've supplied I'd gather it's something to do with preenv or nfshp.
I'd guess there was a problem writing/saving a file and the file system has reverted to read only to prevent further damage.

In the past I've had the same problem when transfering media files, images, mp3s or videos. Just a case of identifying the culprit and manualy deleting it. Not too sure how you'd go about that in your case, but I guess you've now got a few pointers.