Trying to upgrade from 3.0.10 to 3.0.15 I got all the files uplaoded and ran the first script fine but when I run the script for 3.0.11-3.0.12 I get this error:

MySQL Error Occured
1050: Table 'CubeCart_SpamBot' already exists
QUERY = CREATE TABLE `CubeCart_SpamBot` (`uniqueId` varchar(32) NOT NULL, `spamCode` varchar(5) NOT NULL, `userIp` varchar(15) NOT NULL,`time` int(10) NOT NULL default '0', PRIMARY KEY (`uniqueId`), UNIQUE KEY `uniqueId` (`uniqueId`) ) TYPE=MyISAM

Any idea what to do? I know knothing about about php or databases.

It means what it says. The table exists. If you want to remove the error, either remove the table from the database and it will install again or remove the table info from the upgrade script.