[TYPO3] extensions collide when used together

[G.Unger]

hi list

the extensions cr_awstat_realurl and error_404_handling do not work on  
same instalation (T3 4.1.6).

both of them do their work as expected, as long as not installed  
together.

showcase:
- installed cr_awstat_realurl on top of ics_awstats, and the section  
where the pages path/name in awstats is shown, perfectly translates  
the values in e.g. /news/single/archive/2008/06/12/article/prinzipiell- 
erreichbar.html
- installed error_404_handling, works propper and displays the errorpage
- checked awstats in BE again, a new page is displayed -> [realurl]
- any further click in frontend is listed as page -> [realurl]
- uninstall/install cr_awstat_realur in extension manager, and new  
clicks are displayed well again
- unfortunately now the error page now is not displayed anymore,  
instead I get the classic "Reason: Segment "xxxxxxxxx" was not a  
keyword for a postVarSet as expected!"
- uninstall/install error_404_handling again and it workz propper
- unfortunately now every click is tracked as page name -> [realurl]  
again.

I havent got a clue where to start at :(

rgds
GUIDO