Upgrade Problem

[Perplexed]

I downloaded Hoster 3108 and did the upgrade. Now when I try to open I get a message that says "serial number does not match registration information. Please reinstall Hoster and try again". I have done all of the Windows XP updates and have made all the tweaks that the help file suggests. I had to revert to 3.006 in order to use the program. Please advise as to how to fix this problem. Here are my specs:

2600+ AMD XP
ASUS A7V8X-X Motherboard
1 Gig DDR400 Ram
Soundblaster 24 Bit Sound Card
ATI 9200SE Video Card
320 Gig IBM Hitachi Hard Drive
Plextor 52x24x52 Premium CDR

Thank-you for your help in this matter.