Resolution:
RTclient displays the following error:  
  Attempting to reconnect to RTserver. Connect to project on RTserver.
  Using tcp protocol. socket: Too many open files
  Could not connect to RTserver.
  Skipping starting RTserver.
  Cannot reconnect to RTserver.

You can fix this problem by either one of the following:

1. Increase the number of file descriptors using $ ulimit. There are Soft limits and Hard limits. Soft limits are resource use limits applied by default when a new process is created. You can increase these values up to the value of the Hard limit value.
    $ ulimit -H /* display Hard resource limit */
    $ ulimit -S /* display Soft resource limit */
    $ ulimit -n x /* increase the number of file descriptors by x */

2. Limits are applied on a per process basis which suggests you'll have to examing your code to see if you're opening a combination of connections and files that over a given period of time exceeds the Soft limit. You have to su root to increase the value of a Hard limit.

See "File Descriptor Limit" in the SmartSockets User's Guide, Ver. 6.0.