When using a edi mapping model that has a higher schema version number then the Smooks runtime bundled with the eclipse plugin supports, the error message is simply:
Check Input Task configuration. Error creating Input Model from Sample Input Data. Error "..." I'll attached a screenshot of the error.

I noticed this when trying the Smook plugin using the edi-to-java example in Smooks trunk. This example uses the following schema version:
http://www.milyn.org/schema/edi-message-mapping-1.3.xsd
and the version of Smooks bundled with the eclipse plugin only supports 1.2 (I think).

I asked Tom about this and he said that there already is some checking of the versions and perhaps this is only a case on making the error message a little more informative.

The version of the Smooks plugin I used is: 1.1.0.v201002050900N-H208-CR2.