oracle & varchar -problem

hi! I'm new to this list & I have a maybe really old question: I'm using php4 to access an 8.1.5-oracle database through oci8. when i have a varchar2-column (it is 256 or 4000 bytes long) to SELECT from, I get a stange behavior: I get a string which is twice as long as the contents of the varchar2-field and this string contains only 0h-values (null-values). this behavior is shown when I use OCIResult() and OCIFetchInto(), too. however, numbers are displayed correctly. is this a (well) known problem? has anybody a solution for it? any help welcome. thanks in andvance, mac