I made the mistake of thinking that if you double click on the patch26 file after youve put it on your machine (see earlier postings)then it would solve the problem. No. this is how I solved my "divide by zero" error ... because I thought other people were maybe making my mistake.
1) Put patc26 in with a file called fox2600.esl - mine went in c:/uft 2) double click on another file in the same place - mine called . It has a small icon picture that looks as if you want to run in dos mode. 3) this gives you a black screen,like dos prompt, for you to type in commands 4) type I didnt need to do this as the machine did it automatically. But you need to point at the directory that contains Ultimate Family Tree 5) type these command one at a time pressing after each one attrib -r FOXW2600.ESL patch26 FOXW2600.ESL attrib +r FOXW2600.ESL
After typing the patch command I got a message to say that the patch had run and hey presto I could use my ultimate family tree program.