I have done a bit more testing. Looks like it is not the signatures which is the problem (since quotes is also giving the same issue). It appears like another issue with older PHP.
Could you please take a look at this thread and offer me a fix please:
http://www.unicyclist.com/forums/sho...threadid=16654
PS: Thank you for putting up with my old version of php. I don't have much choice in the PHP version, my ISP (pair.com) does not easily upgrade it. (they go through rigorous evaluation/testing process before upgrading).