It appears that COFE wants to transfer the information using a PH flash; I guess that this is a pure compounds stream (else COFE would use a TP flash); to do so, it must set enthalpy on the Aspen Plus stream and this fails. With an invalid argument.
The arguments to the enthalpy call - on my end - appear correct however. Would you be so kind to make a log of this issue to see what the traffic between COFE and Aspen Plus is like? To do so, please do not insert a COFE unit operation into Aspen Plus, but rather insert a COULIS unit operation (presuming you have installed OATS with COCO; COULIS is part of OATS). This will have you select a unit. Select a COFE Unit Operation, and proceed as before. When you quit Aspen Plus, you will be prompted for where to save the log file (*.olg).
Alternatively, you could use the CAPE-OPEN Logger and Testing Tool (COLTT), available from CO-LaN,
http://sourceforge.net/projects/cape-openloggin/Using COLTT you can log with the existing document, you just have to tell COLTT to log unit operations of the type COFE Unit Operation before starting Aspen Plus.