[TYPO3] BE not working after upgrade to 4.2

[Piotr Burda]

Piotr Burda pisze:
> Hi
> 
> After upgrading (from 4.1.2) to 4.2.1, my backend looks strange when 
> using List, screen:
> http://www.narty.pl/em/screen_1.jpg
> 
> Second problem is more serious, when trying to edit content element 
> (pencil icon) i have error HTTP 500 - screen is here:
> 
> http://www.narty.pl/em/screen_2.jpg
> 

second problem is resolved.

after enabling PHP error in Install, i have this error message (when 
trying to edit content element):

Fatal error: Cannot re-assign $this in 
/home/mysite/typo3conf/ext/cal/hooks/class.tx_cal_tceforms_getmainfields.php 
on line 35

found the responsible: old cal extension, after upgrade to new "cal" 
version BE content editing works fine.

Need help with first one

Regards
Piotr