isql utility access error

[Sneevarp]

Hi, I have just installed Sybase on below Solaris machine. Also installed sybase open-clinet software. Entries in interfaces file is correct. When I am trying to access isql utility, iam getting below error.

bash-3.00$ uname -a
SunOS XYZ 5.10 Generic_138888-03 sun4u sparc SUNW,A70
bash-3.00$ /opt/sybase/OCS-12_5/bin/isql -Usa -SXYZ
CS-LIBRARY error:
ct_init(): network packet layer: internal net library error: Attempt to load protocol driver failed
Attempting to obtain a localized error message failed.
bash-3.00$

Could you please guide me.