Question about postgresql-8.1.2-1-binaries-no-installer.zip(win32)

Hi,
I noticed that when I install via the msi setup there is a extra DLL in 
the bin directory called pthreadGC2.dll.  (Posix thread library for windows)

This dll is not in the postgresql-8.1.2-1-binaries-no-installer.zip file.

Postgresql seems to run fine without out when I do a manual install 
using the zip file.

If this is not used for the server what is it used for?

Thanks,

-- 
Tony Caduto
AM Software Design
Home of PG Lightning Admin for Postgresql
http://www.amsoftwaredesign.com