I have a weird mistake, I'm working on Magento (1.5.1) but since I don't know when, installation scripts of modules doesn't work anymore, Magento seems not running SQL folders, for every kind of module. I tried to make a basic external php script using PDO and the same connection setting (host, dbname, loggin, pwd) and that works so I guess it's not a SQL permission problem. I'm totally disappointed.
(sorry for that bad English... of course I'm French)
Have a nice day !
Maybe your scripts have already been executed? Have a look into you core_resources table.
To execute an install script again, you need to have the previous version number in DB: if your script is update-0.0.1-0.0.2, you should have version and data_version to 0.0.1 in order to execute it.
If you want to install it, you shouldn't have any matching row in DB.
edit: You'll also have to clear your cache, of course
PS: your English is fine, at least for an other French :)