I have looked at my /etc/termcap file and it appears OK, I didn't see any corruption present. Please investigate your file to see if corrupted. Verify that you have a TERM variable set properly for you and your users. Should be at the console mode, TERM=linux, if X then, TERM=xterm. Use "echo $TERM" to view setting. If not then, from bash prompt try "export TERM=linux" for console mode or "export TERM=xterm" in X session. You should also be able to verify the two term types in the termcap file. If the TERM variable is not set correctly then investigate the /etc/profile file. I think that is the initial setting at login for console mode.
A possible corruption that is not visible could be created if the termcap file was edited in DOS ASCII mode. It would add CRLF to the end of each line. If the file is corrupted, check for a file termcap-Linux, it should be a copy of the original. Else, copies are on the 2nd CD of the 8.1 distribution under the /live/etc directory. If that is not available then look in the /slackware/a directory of your installation set at the packages there. I think it is the etc-5.0-noarch-7.tgz package. You could attempt to extract just the termcap-Linux file.