[Typo3-dev] Fatal Error: Extension key was NOT loaded! / different (v)hosts / caching problem

[Florian Sprenger]

Hi all,

    i have a very confusing problem right now and after hours of trying 
around i have no idea how to fix it.
I have developed some small extensions that basically just pull stuff 
out of a database and output it. But i don't think thats the problem, 
since when i just let them output a static text the same weird things 
happen.

The extension run just fine and smoothly on my development server at home.

But there seem to be some weird caching problems on the target server.

Only way to access the Typo3 backend is the url 
www.company.com/product/typo3.
I can install the extensions there. They seem to work when i test pages 
there.
If i try to access the pages at www.product.com afterwards i just get a 
message stating "TYPO3 Fatal Error: Extension key "myextension" was NOT 
loaded!".
When accessing the page on www.company.com/product/ i get a message that 
the page will get generated, then i will be forwarded to www.company.com 
(without the product) where the page id does not exist.
If i access www.company.com/product afterwards it shows the page as well 
as www.product.com!

Any ideas what would causing such behaviour?

For me it seems like extensions don't get installed on product.com (for 
reasons i don't understand) but if pages are cached they are working.

Funny thing is there are also a few extension i installed before 
product.com was in function. They all still work nicely.

I mean i think i could bend all the links to the pages where this is 
happening to www.company.com/product, but then i would be stuck with the 
problem that after a cache deletion the first user will get the "page id 
doesn't exist" message, since he does get redirected  to the wrong 
directory.  And i don't want to change all the extension to 
set_no_cache()  either for obvious reasons.

Hope this is the right list for such questions. If not please point me 
into the direction of  right one and i'll repost.

Any hints on how to fix it are very welcome, thank you in advance and 
greetings from Berlin

 Florian