I must apologise. The 32 bit version is installed on this system. (not my box but I should have checked first) The problem still exists but for the life of me I can't imagine why. It still wants to install the German language version and does not show an option to change the language. I allowed the install and sure enough, it was in German. Tried to correct the language preference in Firefox's settings. NG. Still in German. Uninstalled the program and manually installed a downloaded version from the Firefox website. It installed NP, all in english again.
(This message is incorrect. It is a 64bit machine and the 64bit version is installed still updating in wrong language)