I have two copies of Privateer 2, the first version and the Deluxe Edition neither will install. It always says there is not sufficient disk space which is not the case. I have considered buying the gog version but would like to know if anyone has had a problem with the program offered.

Thank you in advance for any help you may lend.

Its likely a compatibility issue with your original copies and a modern computer.

GOG offers versions designed to work with modern systems. And worst case scenario its covered by the 30 day money back thing I would think.

Might try changing compability by rightclicking the installer.

But more people have it too.
https://www.google.nl/#q=privateer+2+not+enough+disk+space&safe=off

http://www.vogons.org/viewtopic.php?t=15012

I didn't have this problem with my GOG version of this game, but I don't have my disk version at hand and can't tell whether it would have occurred with that one.

In many cases, old installers don't work on modern systems (although the games would). The disk space calculation is a common problem since modern drives may have so much free space that old installers can't handle the numbers, and (depending on ho well they were written) might end up interpreting them as negative. GOG uses its own installer, and the GOG version should not have installer-caused problems of older versions.

If you mean 'does the GOG version have the same issue?' I would say almost 100% definitely not as the issue was with the original installer and GOG always re-packages the games into their own custom installers
As for OTHER issues with this notoriously finicky game, I'm not so sure, check the Wing Commander forums, here's a thread from there about a community patch that might help with other glitches:
http://www.gog.com/forum/wing_commander_series/privateer_2_unofficial_patch_thread