I hope I have not already posted this. I looked but could not find it!

When converting from Word 2000 using the Adobe PDF as the printer, the first conversion of the day will not complete. I am running Windows 2000 Pro and have Acrobat 6.0.1. The icon spins in the system tray and then gives me the message it converted. But it leaves a file on my desktop that is unrecognizable. If I add the .pdf extension it works fine. Any ideas?
Thanks!!