The rmem_default value of both servers has been set to 65535 and rmem_max set to 131071, but in the "RAC on Linux Best Practices" (Metalink Note: 240575.1) article, Oracle strongly recommend to adjust the send and receive buffer size to 256K.

#The default setting in bytes of the socket receive buffer
/proc/sys/net/core/rmem_default = 65535

#The maximum socket receive buffer size in bytes
/proc/sys/net/core/rmem_max = 131071

#he default setting in bytes of the socket send buffer
/proc/sys/net/core/wmem_default = 262144

#The maximum socket send buffer size in bytes
/proc/sys/net/core/wmem_max = 262144

Do you think this may cause the error?

I also found a Bug: 2642168 - Buffer overflow vulnerability with CREATE DATABASE LINK, but Oracle claims that this bug is fixed in 9.2.0.3.0.