Hi,
Have you marked the "Header Rows to be Ignored" as 1?
Make this setting and try activating.
If it is still throwing error share the same, also try running the program RSDS_DATASOURCE_ACTIVATE_ALL. You have to go to se38 and enter this program name. and then you can click on 'execute' button, and give the data source details and then click again on execute.
Hope it helps.
Regards,
Rathy