In my attempts to link MODFLOW to my project, I am always getting a message indicating that there is an error in reading name file. YOU will find a screenshot of this message attached to this email. Could you please show me how can I solve this problem?

The error message you got -- "DRT package not allowed if linking to WEAP" -- is accurate. You cannot link a WEAP model to a MODFLOW model that uses the DRT (Drain Return) package. This is because the DRT package duplicates calculations that WEAP is doing, so would be double counting. You must remove the DRT package from the Name file if you want to link it to WEAP.

Jack