The standard maintenance cleanup task will not remove files that are not native backup files. Since you are using a 3rd party backup utility (SQL Litespeed?), you need to use their tool to cleanup backup files, or roll your own utility.

Since you are trying to cleanup files that are a couple of hours old, I am guessing that these are either differential or transaction log backups. If so, are you making sure that these have been copied off somewhere else (tape, network share, etc...)?

If not, then you are going to have a problem with recovering the system in the event of a disaster. Before deleting any backup files, you definitely need to make sure you have a restorable copy of the backup file somewhere.

Jeff