While attempting to install BullzipPDFPrinter_6_0_0_865 on Windows 7 and am getting a similar error.
c:\Windows\system32\msscxript.ocx
Unable to register the DLL/OCX: RegSvr32 failed with exit code 0x5.
Abort Retry Ignore
I clicked Ignore like a previous poster suggested and continued with the installation. Seems to be working fine. I'm sure the .ocx file that is mentions was already registered in Windows 7. Just thought I'd post this to let you know.