so i am guessing here that
after you installed BT5 to a usb thumb drive
and you are booting to the thumb drive that BT is not able to use the printer
( cannon is very well known for NOT supporting linux)
printing is one of the things at the very bottom of the list of things to do with BT
getting into a network unseen and without leaving any trace is #1, printing is below #10000 on the list .
is this a VM install
a install to the drive
but Backtrack was designed BY security experts for use BY SECURITY and network EXPERTS
Experts that have the LEGAL permission to test the network security of the client
have you gone through the BT tutorials ?
they are for the old bt4 and YOU will need to port them for use in bt 5
and go through the wiki
also it is recommended that you take the "offensive security " classes