[TYPO3] Webformat extendedshop no_cache

[hartmut]

Hello list,

I installed extendedshop and now all my pages (not only the shop) are 
set to no_cache=1.
When I uninstall, the pages are cached again.

Is this a bug in extendedshop or could I have a fault in my installation?

My versions of typo3(4.1.2) and php(5.2.1) are higher than recommended 
for the extension. Could this be a problem?

Thanks in advance
hartmut