[Koha] Z3950 Access and Public IP Address

Hi All. I am wondering if it is possible to access Z39.50 without direct Internet Access. I once connected my server directly to the Internet and I was able to import records from z3950.loc.gov server. Now I am connected indirectly via a another computer. I can go ahead and get z39.50 results, but I cannot import. I am getting this error: Can't call method "add_subfields" on an undefined value at /usr/share/koha/intranet/cgi-bin/cataloguing/addbiblio.pl line 141. I believe the error has do to with how I am conncted to the Internet because if I have a direct connection to the Internet, I can import the records. Regards, Admire Mutsikiwa