[TYPO3] funny problems with T4.2

[Costa Papadopoulo]

Hi all,

newest TYPO3 4.2, running on php 5.1, ubuntu latest server, all updates.
All exts from T3 are up to date. I am using also TV.

BTW:
I only have the funny problems in this vhost all other t3 4.2 installations 
on the same server are ok.

Ok now the probs ..... be prepared!
;-))

i have a 4.2 TYPO3 running, moved it from 4.1.6 no probs.
Did a compare db -> everything is ok
Compared tca -> everything is ok

But when working in BE funny things happen.

When I edit an element, the header is always empty, even when entering 
something, after save everything s gone.
Also  RTEhtmlarea 1.7 (newest) does not load. I did debug mode, rte sais 
everythings successfully loaded, but not RTE appears.

Also when looking in BE with firebug I have 8 errors, they are the 
following:

evalFunc is not a constructor
jsfunc.tbe_editor.js()()jsfunc.t...editor.js (line 557)
[Break on this error] var evalFunc = new evalFunc();
jsfunc.t...editor.js (line 557)
evalFunc is undefined
[Break on this error] evalFunc.USmode = 0;
alt_doc....452]=edit (line 722)
evalFunc is undefined
[Break on this error] evalFunc.USmode = 0;
alt_doc....lettes]=0 (line 722)
evalFunc is undefined
[Break on this error] evalFunc.USmode = 0;
alt_doc....lettes]=1 (line 7222)

What the hack is going on there in the BE ?

I am totally confused whats going on. I don't know how to go on.
I installed new 4.2 source, but everything s the same.

I am looking to get  this fixed since 2 days - no sucess.
:-((

This is driving me really crazy.

Anyone has a hint or suggestion?
Would be highly appreciated!

Thanks
costa