Any ideas would be most appreciated

I don't believe you

I asked how you installed http://kobesearch.cpan.org/dist/mod_perl, and your response was Re^2: How to install Apache2::Ajax

Yes, its is dead obvious that Apache2::BuildConfig doesn't match your setup -- this isn't the fault of Apache2::BuildConfig

the only way that would happen, is if you didn't build Apache2::BuildConfig yourself

So either install apache2 where Apache2::BuildConfig expects it, or edit Apache2::BuildConfig to expect it someplace else, or build mod_perl yourself