I had a similar problem on a couple of our Linux boxes. This happened right after we installed Sybase.

The culprit was, the /etc/ld.so.conf file was empty. The Sybase installation erased these files for some reason. I put back the entries in the file and everything was OKAY.

Here is how my /etc/ld.so.conf file looks like

/lib
/usr/lib
/usr/X11R6/lib
/usr/kerberos/lib
/usr/local/lib
/usr/X11R6/lib
/usr/lib/qt-3.1/lib
/usr/lib/mysql