NWDS - MAM Error

Hi everyone, I'm hoping you could help me resolve a problem I'm having.

I have imported the MAM25 Eclipse version of MAM into NWDS, exported it, and ran the application successfully.

My problem is as follows:

I would like to make a modification to the equipment list, and add a new field. Referencing the Enhancement Guide, the first step is to create my version of the ListDef.xml file. I double clicked the ListDef.xml file to just check the source code. When I did this, NWDS did a compile on the file and found a bunch of errors. Here is one example:

The content of element type "data" must match "(type,instanceOf?)". ListDef.xml MAM25/app-root/WEB-INF line 1403

I haven't even made a change yet, and it seems the core program delievered from SAP has errors.

Can someone please explain why this is occuring?

Thank you.