I had some troubles running Umbraco version 4 on a MySQL database version 4. I developed a website on a MySQL V5 database, which works fine. The problem occured when I tried to place a backup on the live environment which appeared to be MySQL version 4.
The following error message was shown:
ERROR 1074 (42000) at line 1947: Column length too big for column 'EMAIL' (max = 255); use BLOB or TEXT instead
It seems that you cannot use varchar(1000) on MySQL 4. In the backup script (which is an sql file) I replaced all varchar(1000) into TinyText (thanks to my colleague Arno Raps) and as far as I can see now, it works fine.
Unfortunately, this problem is not well documented on Umbraco, so I just post it here...