I had just gotten this error, I found what it meant and started to slowly to delete the models of which I had just added before I got this error (map complied fine before I added some models)
************ ERROR ************
Line 3948 is incomplete
During this clean up, my map deleted half of my work its gone and somehow it even clean my back up map file I have no idea how this was done but I would like to warn newbie mappers such as myself to becareful of this warning it ain’t nice.
yes its a very good idea to back up your maps. Sorry if you have lost half of yours. Just reading this is making me back up files again
as with any significant piece of work, one should never rely on the autosave and backup system. I still recommend Saving As [mapname]- several times a day. That way, it’s easy to go back to an earlier version and have a good idea of what stage it will be in.
Also, just before compiles, I’ve gotten into the habit of Saving As [mapname] to eliminate the tons of folders, .prt files, etc that clog up my /maps folder if I don’t.
Cheers
Trust me fellas I had a couple of back ups as follows:
Capture.map (main file)
autosave.map (1 backup)
Capture1.map (2 backup)
Capture3.map (3 backup)
All the way to Capture5.map, hehe I have a serious thing about making backups of any work I do on here.
As I did say before it took out my back ups aswell I don’t know how it done this but it done it.
Thank gawd to my quick thinking I remembered I already had it complied and working from where I last left off offically. Hence I quickly decomplied it, deleted everything from the main file and copied everything back over except for a few small things which won’t take long to rebuild. Hopefully now it will work once again, too many hours have gone in already.
I’m sure everyone knows what its like to lose a map with so many hours in it.
And remember all newbies to always back up your work alot on hard drive, disks or cds 
If you decompile your map and then use it going forward, be aware that you lose ALL of your structural and detail information. A decompiled map will be completely structural.
Thats ok all my brushs where structural, I hadn’t yet gone through and changed to detail, but thank you for letting me know about that I had no idea