Vi not recognizing terminal type

[Mike Rathburn]

This isn't really off topic since I need to adjust the termcap to make
filePro play nice...

I'm on an old Sun system where 'vi' does not recognize any terminal type I
throw at it.  Ex:

$ vi /etc/termcap
At386: Unknown terminal type
I don't know what kind of terminal you are on - all I have is 'at386'.
[Using open mode]

Running filePro in most term types works okay (even the at386 above).  Just
need to do some adjustments to others.

What makes vi not like the term types?

Thanks.

-MikeR