Unable to add new term

Hello,

I am new to Drupal and exploring various modules from user perspective, though I can tweak a little bit of code and database myself. Node relationship module is very interesting and I tried to experiment with it.

I had Drupal 4.7 beta5 installed (on Apache2, Php5). Found out that node relationship module works on 4.6, hence did a virtual host and installed Drupal 4.6.5.

On enabling relationship module, I got errors on $HTTP_POST_VARS which I changed to $_POST and similar one for $_GET (I think this is due to PHP5)

The module works and brings up initial page from admin menu. However, when I choose to Add Term, it fails.
I get following errors.

invalid argument [NULL] to relationship_get_longname(). Expected a string. 1
: in relationship_get_longname(), line 847 relationship.module : in _relationship_form_term(), line 408 administer_predicates.inc : in relationship_admin(), line 165 administer_predicates.inc 0.00s elapsed. (0 total)

warning: Attempt to assign property of non-object in D:\drupal-4.6.5\modules\relationship\administer_relationships.inc on line 155

When I remove the call to relationship_get_longname from line 408 in administer_predicates.inc, I get only the warning given above, but still page does not come up.

Is this also related to php5? Is there any workaround to get it work and experiment?

Thanks,
Patrick