I've tried to install portable firefox on both a 32MB thumb drive and a 128MB thumb drive without success. After I download the zip file to a folder on my desktop, I unzip it and move the files to the root directory of the thumb drive. Next step says to double click on PortableFirefox.exe. When I do this I get this message "firefox.exe was not found. Please check your configuration". The install instuctions seem simple enough. What am I doing wrong. Thanks.