My Son is was making a map and he did something that when he saved the map he ending up with what he called a Fatal Error.  Now his map will not open and he thinks he has lost everything.

Has he lost everthing or is there a way to recover his map?

When opening the map the message says
"ParseEntity:{not found
GetLastError() = 0
An unrecoverable error has occured. Would you like to edit Preferences before exiting Q3Radiant?"

Sincerly,
Sir Bors and Son

This little icon really expresses my feeling about how many things broke or went wrong when I was trying to do something this weekend!!!1

Unfortunately, it's been so long that I don't remember the details, but I think there is a way to recover the corrupted file...  Involves text editing the .map, IIRC...  Have you tried Google yet?

It's been a long for me as well...
Hope you can solve it, and for future mapping: I always save my maps with increasing numbers: mapname_0001, mapname_0002, this way I can always get the last working map if something goes wrong (be warned, numbers will rise very fast, especially if you're as cautious as I was, I ended up with over 200 mapsaves).

I try to google it.  I came here first because you guys always seem to have the answer.
Nice to see Agent007 still around.

I still have interest in all of this but life gets in the way of my having fun.  And my son is a senior now and working so he does not have as much time either.  Or yeah and girls tend to take up some of his time too.

Sincerely,
Sir Bors and Son

Heheh.  How old was he when you first started posting here?

And I agree w/ Spook.  You should never save over the same file.

Anyway, a few google results:
http://forums.filefront.com/showthread.php?t=8190
http://www.qeradiant.com/faq/fom-serve-arch/cache/133.html
http://72.14.203.104/search?....k&cd=14

Hope that at least gets you pointed in the right direction...  Looks like it's fixable via a text editor, or a small app someone created.  Although the link to the app's homepage is dead...