Recent upgrade to Apache-2.2.3 secured down on executables not able to be included within a SSI include call and was getting "unable to include potential exec" in the apache error log file.
Apparently .shtml files were being used as includes via SSI. Changing the included files to .html resolved the issue.
Below was the command issued from the document root to quickly rename all the embedded leftmenu.shtml to leftmenu.html:
cp -a leftmenu.shtml leftmenu.html
find -L -name "*.shtml" -type f -printf "\"%p\"\n" | xargs perl -pi -e 's/leftmenu\.shtml/leftmenu\.html/g'