can someone help me with some details explanation for using the export cdt to ex

What errors do you see in the UI and in the application server log? If you're pulling data from DB2 to a CDT array, you may need to check that the CDT array is being populated correctly prior to the export.

In the UI doen't give me any error, if I look at the alerts the message is:
Problem: An error occurred in executing an Activity Class.
Recommended Action: Examine the activity class to correct the error and then resume.
Priority of this problem: High Priority

I found in the log's something like this: [9/14/15 9:09:02:655 GMT+02:00] 000002d4 SystemOut O 2015-09-14 09:09:02,655 [WebContainer : 7] ERROR com.appiancorp.analytics.excel_export.ExportCdtToExcel - The input fields does not match the fields in the CDT
Probably you are right.
What I do in my process:
1. I habe a script task that get's the cdt data in a process variable.
2. I configure export and ad as a cdt the process variable.

For what I saw in the process variable the array is ok.
Can you explain to me, what I should do?

I found the error. It was seeing my array of fields that I wanted to extract as a text. I putted a wrong comma.
Thanks a lot for the help.
The plugin works great also for DB2.