Archfool - thanks for your reply, below are the results of the ldd command.

        libsybct.so =>  /sybase/OCS-15_0/lib/libsybct.so
        libsybcs.so =>  /sybase/OCS-15_0/lib/libsybcs.so
        libsybtcl.so => /sybase/OCS-15_0/lib/libsybtcl.so
        libsybcomn.so =>        /sybase/OCS-15_0/lib/libsybcomn.so
        libsybintl.so =>        /sybase/OCS-15_0/lib/libsybintl.so
        libsybblk.so => /sybase/OCS-15_0/lib/libsybblk.so
        libdl.so.1 =>   /usr/lib/hpux32/libdl.so.1
        libm.so.1 =>    /usr/lib/hpux32/libm.so.1
        libsybcs.so =>  /sybase/OCS-15_0/lib/libsybcs.so
        libsybtcl.so => /sybase/OCS-15_0/lib/libsybtcl.so
        libsybcomn.so =>        /sybase/OCS-15_0/lib/libsybcomn.so
        libsybintl.so =>        /sybase/OCS-15_0/lib/libsybintl.so
        libm.so.1 =>    /usr/lib/hpux32/libm.so.1
        libsybunic.so =>        /sybase/OCS-15_0/lib/libsybunic.so
        libsybct.so =>  /sybase/OCS-15_0/lib/libsybct.so
[download]

I also tried re-installing DBD::Sybase in both the 32 bit and 64 bit builds using the 'perl Makefile.PL -r=buildXX' where XX is the bit depth. Unfortunately the 'Can't make loaded symbols...' warning came up for both builds during the 'make test' session.