Issues connecting to Siebel Clustered Servers

We are getting the following error message while connecting to one of our Siebel End Systems in the integration.
Could not connect: [BASSIEB.1000.0002]CoreServices.checkRepositoryConnection - poolMgr.getConnection threw this: type(com.wm.siebel.ConnectionPoolException), msg([BASSIEB.5000.0008]ConnectionPool.ConnectionEntry.ctor - NSReadKey request failed (no error information). - connection.connect fails; returns false)

In this instance, we are trying to connect to their Siebel Clustered servers. We are using the right Gateway and Siebel Servers. However, we get the above error messageā€¦ We are running IS 6.01 with Siebel Adapter Version 3.0. Our adapter works fine with an individual standalone Siebel Server. and we get the above error only while connecting to the Siebel cluster. Can anyone shed some light on this, Pleaseā€¦