Original UW 7.1.3 install or upgrade from UW 7.1.1?
Drivers for the 29160 card were not included in the UnixWare 7.1.1 media, and if you did an upgrade, they new drivers would not have been brought in unless you have first applied hba711a driver supplement:
ftp://ftp.sco.com/pub/drivers/UW711/storage/
That said, I assume you attempted to install the tape drive? During installation, what scsi adapter driver did you choose?