[win32] 8.3.5 -> 8.3.7 install trouble

I went to upgrade an installation and was stopped with (approximately)
the following message after clicking Next on the step where I told it
to use the same data directory:

"The existing data directory (date time: floating-point numbers) is
not compatible with this server (date time: 64-bit integers)."

This is with the EDB postgresql-8.3.7-1-windows.exe that I found on
postgresql.org. Apparently for 8.3.5 I had found a .zip file
containing an .msi. I think the new text threw me--I remember the
install being easy, and the .msi mentioned stuff about Group Policy
and other advanced options and I thought, "Well, I don't need anything
that fancy."

Just a warning in case someone else was thinking they were compatible.