For a friend of me I made an informative website for his shop (not an online shop), using the Zend framework. I needed a little database (to store the pages of the website and some pieces of HTML code).

Because my friend already had a webhosting, but one which doesn't support databases like MySQL I decided the job could also be done with SQLite, which was supported by the webserver.

Locally the website worked without any problem, and after uploading the website yesterday it worked also for a while. But after an hour or so I checked if the site was still up and running but then I got a Zend_Db_Statement exception (after loading for approx. 30 seconds) with message:
'SQLSTATE[HY000]: General error: 5 database is locked' in *****/library/Zend/Db/Statement/Pdo.php:68

I tried several things to 'unlock' the database like uploading the database file again or changing the file permissions but it didn't help. Only after a while the lock was released automatically.

After that I have checked regularly and found out that approx. half of all tries the database was locked. Sometimes it worked, even after some page refreshes or administration tasks (which modified the database) but suddenly the database was locked and only after a while the lock was released (automatically?)

Does anyone know what could cause this problem or should it be better to drop the SQLite database and switch to a 'real' RDBMS like MySQL (but then my friend have to upgrade his webhosting).