trouble with rpmbuild on WBEL3.0/x86_64

Hi all,

I wanted to install postgreSQL 7.4 on my ia32e box (x86_64 dual xeon PL370G4) running WBEL3.0.  I looked for binary
RPMsbut did not find any. So I tried to 

rpmbuild --rebuild --define 'build9 1' postgresql-7.4.6-2PGDG.src.rpm

but during configure I get the error

....
checking for python... /usr/bin/python
checking Python installation directories... /usr/lib/python2.2
checking how to link an embedded Python application... no
configure: error: Python Makefile not found
Fehler: Bad exit status from /var/tmp/rpm-tmp.75919 (%build)

python-devel-2.2.3-5 is installed. On a similar i386 system (same versions of rpms), this error does not happen; here I
couldbuild all RPMs successfully (but, of course, not for x86_64). 

On my x86_64 system, rh-postgresql 7.3.6-7 is still installed - I thought I could rebuild newer RPMS before removing
theold ones. Should I remove rhdb first? 

Did anybody succeed in building x86_64 binary rpms? Any ideas?

Regards
--Marcel