nahua and rhyguy,
I have an update that may help.
There was a post in another forum that helped me find that I had a permission problem with the RT2500USBWirelessDriver.kext folder. Once I got that fixed the RT2500USBWirelessDriver.kext driver load successfully

So now in the System Preferences Network application I was able to configure the WUSB45G adapter as en1 and bingo - I was connected. But after a bit of snooping I found out that my adapter was connectiing to an open Linksys router in my area - not my router; the dhcp assigned ip addresses were not from my router.
So I launched the Ralink USBWirelessUtility to configure my adapter. The trouble is that the application always displays "No Device !!!" and no matter what I try to do I can not get this application to work
I also found that there should be 4 .Plist files in my ~/Library/Preferences folder but they are not there

They are:
• ~/Library/Preferences/AdvancedProfileSetting.plist
• ~/Library/Preferences/ActiveProfileSetting.plist
• ~/Library/Preferences/Profile.plist
• ~/Library/Preferences/com.Ralink.RaConfig.plist
I wonder if this could be part of my problem ?
If you have any ideas or suggestions I certainly would appreciate any input.
Many thanks,