Okay, here's the answer:

Like the previous commenter said, to get Sybase to install you have to read the suggestion here:

http://www.mail-archive.com/dbi-users@perl.org/msg31071.html

Those symbols are missing from the FreeTDS include files.

Edit dbdimp.c, and somewhere near the top add:

#define BLK_VERSION_150 BLK_VERSION_100
#define BLK_VERSION_125 BLK_VERSION_100
#define BLK_VERSION_120 BLK_VERSION_100
[download]

Then recompile.

Also, do not try testing using the scripts here: http://www.freetds.org/userguide/perl.htm#DBD.SYBASE

Because there is no Sybase public server since about 10 years ago, apparently. Definitely not now.

Also, you have to remember that if something freezes up and you get irritated and shut down your machine, when you turn it back on you have to reset your SYBASE environment variable or it will not find the driver that freetds comes with. Doh.

Thanks for all your help! I definitely understand the way it works much better now that I looked at it really closely at the least.