The symbol kgefac_ should be in the Oracle shared library libclntsh.so.

With objdump -t (or nm) you can find out whether libclntsh.so does in fact provide the symbol, or not (e.g. wrong lib version):

$ objdump -t libclntsh.so.10.1 | grep kgefac_
[download]

(first find out where the lib resides, of course)

And ldd will tell you if your Oracle.so maybe hasn't been linked against libclntsh.so at all (problem at build time):

$ ldd /usr/lib/perl5/site_perl/5.8.5/i386-linux-thread-multi/auto/DBD/
+Oracle/Oracle.so
[download]

(In case it has been linked properly (so it would try to load the lib), but the lib cannot be found at runtime, you should have gotten a different error ("... cannot open shared object file: No such file or directory", or some such).)