I wouldn't use import/export at all; it can be flaky.  Here's what I'd do:

1)  On PC #1, create a new .PST file (File | New | Outlook Data File) --
when it opens in the Folder List, copy the Contacts folder from your
original .PST file to the new one.

2)  Close the new .PST file out of Outlook by right-clicking the root folder
and selecting Close.  Close Outlook (to make sure the file is not locked),
then copy or move the .PST to the CD.

3)  Take the CD to PC #2 and copy the file onto the hard drive there, then
remove the read-only attribute from the file (right click it in Windows
Explorer and select Properties, then clear the Read Only checkbox).

4)  Open Outlook on PC #2 and open the .PST file using File | Open.  Now you
can copy or move the contacts from this secondary .PST to the main .PST.
You will probably need to open the Contacts folder in the new .PST file and
drag individual items, rather than dragging the whole folder (you can drag
them in groups, though -- use CTRL or SHIFT to select multiples, or CTRL+A
to select all).

One other thing to note:  A new Unicode format .PST file created in Outlook
2003 will not work in older versions of Outlook, so if you need to copy
contacts from Outlook 2003 to an older version, make sure the new .PST file
you create is in the old "Outlook 97-2002" format.  You'll get this choice
after you click File | New | Outlook Data File.  .PST files created in
Outlook 2002 or earlier will work in any version of Outlook.