DBD::Oracle connection problem, ORA-06401

[Ian Jones]

On WinNT (service pack 6) I've installed:
ActiveState Perl 5.8 (805)
DBI 1.32 and DBD Oracle 1.12 from the ppd's at http://xmlproj.com/PPM/

When running a test connection script (see below) I get "Error while
trying to retrieve test for error ORA-06401"

I'm running against Oracle 8i (8.1.7).  When using sqlplus, the host sid
is fine.  My oracle home is indeed "C:\oracle\ora81"

Thanks!
Ian

#!C:\Perl\bin\perl

 use DBI;
 use DBD::Oracle qw(:ora_types);
 $ENV{ORACLE_SID} = "dbdev1.mydomain.com";
 $ENV{ORACLE_HOME} = "C:\oracle\ora81";
 $dbh = DBI->connect("dbi:Oracle:dbdev1.mydomain.com:",
 "reportuser", "rptpwrd");

 $cursor = $dbh->prepare("SELECT TABLE_NAME FROM
 USER_TABLES WHERE TABLESPACE_NAME='USER_DATA'");

 $cursor->execute;

 while (@row = $cursor->fetchrow_array) {
   print "$row[0]\n\n";
 }

 $cursor->finish;

 $cursor->finish;