Just to verify, were the FileMaker services stopped when you updated the Apache version? You may need to perform an un/re-install of the software. I know that this is not the resolution that anyone likes to hear, but it is usually the most effective in these cases.
I definitely stopped apache. I uninstalled FM Web Publishing 8.0v4, then re-installed it. I checked that all the files were rewritten.
I suspect that rebuilding apache ( although I did it from the 10.3.9 Darwin source) has somehow introduced an incompatibility at the level of loading an 'old' dynamic library module.
Basically , I have a horrible feeling I'm screwed....