Install page not working ?

[cabjixx]

I uploaded the files, and started to create the database (there's also an extra table not pertaining to the adoptables system in there).
When I go to the install page, I get:

Internal Server Error
The server encountered an internal error or misconfiguration and was unable to complete your request.

Please contact the server administrator, [no address given] 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.

What could be causing this ?

Also, when I add the adopts_adoptables table, the MySql doesn't allow it...?