Yep, I changed the theme to another it works, but I still cannot access Plug-ins or updates.
I just get:
Internal Server Error
The server encountered an internal error or misconfiguration and was unable to complete your request.
Please contact the server administrator, webmaster@kehonrakentamo.fi and inform them of the time the error occurred, and anything you might have done that may have caused the error.
More information about this error may be available in the server error log.
Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.
Apache Server at kehonrakentamo.fi Port 80
I will ask the host to increase the memory, but I though 64mb was supposed to be fine...