You may see this error when the process tries to load too many classes for execution.
Below is one example of a setup that could trigger this:
1. the process uses multiple versions (2011.2 and 2010.2) of the NetSuite connector
2. it also loads additional custom libraries in a custom script
To resolve the issue yo may need to limit the use of different versions of the same API. In the above example you could choose to use either the 2011.2 or the 2010.2 of the NetSuite connector.