Ultrium 448 tape drive spits out tapes

How old is your cleaning tape?
How about the Ultrium 448, how old is it.
cleaning tapes do not have an infinite life, nor does a tape drive.

That suggests a hardware problem. If you have a service contract or warranty on the drive, get that going. If not, I'd try cleaning the drive with compressed air, or if you can open it check if there is any debris or some other stuff that doesn't belong in the drive and clean that out.

If the blank tapes you tried are used tapes, I'd also try a new tape.

PS, you didn't mention ultrium 448 model or server OS, but here is a diagnostic tool that may work:
http://h20000.www2.hp.com/bizsupport/TechSupport/SoftwareDescription.jsp?lang=en&cc=us&prodTypeId=12169&prodSeriesId=327382&prodNameId=501413&swEnvOID=4024&swLang=8&mode=2&taskId=135&swItem=co-97987-1

Thanks for the info, it is a HP Ultrium  2 448 mounted on a windows 2003 server, the tapes are brand new out the box, media type hp lt03 ultium rw, i am estimating this tape drive has been there for more than 3 years, i just
started working here about a year ago.

are HP LTO-3 Ultrium 800 GB Rewritable Data Cartridge  compatible from what i am seeing they are

the HP Ultrium 448 is a LTO-2 device and is 200GB native (400GB @2:1 Compression)
LTO-3 is 400GB native (800GB @2:1 Compression)

Your drive won't write to a LTO-3 cartridge.

From http://www.lto-technology.com/About/faq.html

What are the backward compatibility characteristics of the Ultrium format?
The LTO Ultrium compatibility is defined with two concepts demonstrating investment protection: 1) An Ultrium drive can read data from a cartridge in its own generation and two prior generations. 2) An Ultrium drive can write data to a cartridge in its own generation and to a cartridge from the immediate prior generation in the prior generation format.

For example:
- An Ultrium format Generation 5 drive will read and write data on an Ultrium format Generation 4 cartridge as specified by the Generation 4 format and read data on an Ultrium format Generation 3 drive.

- An Ultrium format Generation 4 drive will read and write data on an Ultrium format Generation 3 cartridge as specified by the Generation 3 format and read data on an Ultrium format Generation 2 drive

thanks for the information being that said, i can only purchas the 200gb for it