When you encounter an unmarshalled Exception such as:

java.rmi.UnmarshalException: error unmarshalling return; nested exception is:
java.io.InvalidClassException: fluximpl.ActionFlowChartImpl; 
local class incompatible: stream classdesc serialVersionUID = -3144672889935971456, 
local class serialVersionUID = 4929965274834174282

When exporting a flow chart there are two possible causes.

1. Version mismatch

The Flux Designer and Flux engine need to be of the exact same version in order for you to export jobs from the Designer to the engine. For instance, a Flux 7.0.7 Designer cannot connect to a Flux 7.0.13 engine.

2. Firewall

If your engine is on a separate machine from your Flux Designer, you may be encountering a firewall issue. There are two ways Flux can traverse firewalls, simple traversal and IP tunneling.