BUG #6265: Installation failure at the very beginning

The following bug has been logged online:

Bug reference:      6265
Logged by:          Clovis Vieira Jr.
Email address:      clovis.svj@hotmail.com
PostgreSQL version: 9.1.1-1 win 64
Operating system:   Windows 7 - 64
Description:        Installation failure at the very beginning
Details:

When it starts to install postgresql it gives an error message: "Unable to
write inside TEMP environment variable path".

I tried to install under Administrator account as i also ran as
administrator the instalation package.

I use comodo firewall wich i de-activated.

I uninstalled my anti-virus software(avast).

I turned off the windows UAC.

I verified windows host scripting wich was enabled.

It is a home pc in a homegroup network.

I hope some of you can help me.

Thanks.

Clóvis.