UnrealED Saving Bug

[wauzie]

Hello,

I'm creating my own custom map at the moment, but i'm kinda stuck in the process, because i can't save my staticmeshes properly anymore.
Here is a screenshot:

Click

What happens is the following:
I want to add/replace one of my staticmeshes as shown in the image. Nothing seems to be wrong, until i test my map. The model doesn't show up in game and when i restart the editor and open the staticmesh package, the models disappeard! This is very strange, because i save the packages after i edit them.
I think it has something to do with the temp file not being completed or something like that. (My Harddrive has 5 gb space left, so that's not the problem).

Do you guys know what problem i'm coping with?

Paul