[Koha] problems with koha ILS-DI 'HoldItem' function

Hello all, as the suject suggests, if i try to hold an item using the following method: http://localhost/cgi-bin/koha/ilsdi.pl?service=HoldItem&patron_id=1&bib_id=140&item_id=9339 i am getting an error like this one: Software error: Can't use string ("1") as a HASH ref while "strict refs" in use at /usr/share/koha/lib/C4/ILSDI/Utility.pm line 88. Note: if the item does not exist, then it returns an xml sheet with 'record not found' but if everything exists, then i am getting the above error. just to inform, i can get item details or patron details through the ils-di without any problem. Any help will be appreciated. Thankx, Auninda