Squirrelmail - cannot create folders

[wapa17]

Hi,

I decided to change from UebimIau to Squirrelmail and I installed the packagefile from IspConfig, read the "10 steps".

I simply cannot create folders in the Squirrel-mailclient .. it gives me the following error-message, when I tried to create a folder "important":

---cut ---
ERROR: Could not complete request.
Query: CREATE "important"
Reason Given: CREATE failed: Can't create mailbox node /var/www/web1/Mail/important: Permission denied
-------------- cut ---------------------

Thinking logically: I think the route must be "/var/www/web1/web1_someusername/Mail", or I am wrong ?

One additional question is: how to remove UebiMiau from Ispconfig ??

Thanks in advance...