Im not sure about that one. Please call your pharmacist and they will be able to tell you for sure. If the pill has a little line across one side of it, then it is likely to be ok to cut it, but check to be sure.
If this is an ER medication, then breaking it in half may mess with the extended release mechanism and cause major problems for you. I think you should call your prescribing doctor and ask if he can write you a scrip for the IR tramadol instead.
Please do not break it in half and take it until your doctor has said it's ok and safe to do so.