You should make sure to have all the latest patches installed - however this is not related to your current issue.
If you are currently unable to re-install the extensions I'd suggest temporarily disabling them. To do so just rename
app/etc/modules/Fooman_PdfCustomiser.xml
to
app/etc/modules/Fooman_PdfCustomiser.xml.off
and then delete the var/cache directory to refresh the cache. This will at least get you past the error message until you can get things re-installed properly.
