Did you make sure you have root access with Titanium Backup?
TB requires root in order to function. Once you open TB, you should see the 'overview' screen, then below that, you should see a check for root access, and an 'OK--->tap for more info<---. Touch this to open a secondary screen, if you have root access, this will tell you in this manner:
Root access: OK (BusyBox 1.19.4-Titanium from app)
SQLite:
YES (SQLite 3.7.6.3-Titanium included)
If another message shows an error, then you do not have root access, and TB will not run.
If you do have root access, you wil see another green check next to the backup directory, showing the path/location of where this information is stored, such as: /mnt/sdcard/TitaniumBackup.
You have three icons to actuate, on the left, you have the main one for overview, then the backup/restore icon, then finally, Schedules, where you pick the method and type of backup you desire. Here, under 'edit' you make these selections, as well as how often, and the time you request.
Once you completed your initial backup schedule, you should run it, and once that has occurred, you will see a notification below indicating the next action by date and time the following backup will take place.
Just make sure to touch the check box of the TYPE of backup, as there are to choices, with the top selection being only for MODIFIED data, and the second selection for backing up all user apps and system data.
You have more selections available than what I showed, but you have to scroll through them both and find the backup type that best suits your needs.