This is weird, because your error message says that DB_File.pm contains a syntax error. Maybe the Perl that is run by your webserver to run your script is a different Perl than the one you get through ssh. I suggest removing all other code from your search.pl (or better, creating a new file) that only has the lines

#!/usr/bin/perl -w
use CGI::Carp 'fatalsToBrowser';
use DB_File;
print "DB_File is OK\r\n";
[download]

in it, to see whether DB_File on itself loads OK.