Cant allocate space for object

Hi!
I'm running mssql 6.5 and I've got a problem with a pretty basic errormessage. I've managed this scenario before, but I't doesnt seem to work this time...
The message is:

Can't allocate space for object '-482' in database 'tempdb' because the 'system' segment is full. If you ran out of space in Syslogs, dump the transaction log. Otherwise, use ALTER DATABASE or sp_extendsegment to increase the size of the segment. (Message

What I've done so far is:
dump transaction tempdb with truncate_only
Dump master ...
I've expanded the tempdb device (alter database)

Now I'm starting to run out of ideas...
What's this '-482' (I've also got an error on -386 once)
Anybody have any idea what to do next?

Thanks!!That is the ObjectId of the table in the database.