3458381 - DTP execution failed with exception 306126

You have the following scenario:

• Source for DTP is a HCPR;
• The HCPR has a HANA CV as part provider;
• The HANA CV has a mandatory input parameter;
• The DTP has a routine as filter.

And the DTP is failing with error:

Instantiation of calculation model failed;exception 306126: An error occurred while instantiating the calculation model:
There is neither a default value nor a data input mapping for the mandatory variable $$<variable_name>$$ of the scenario <scenario> (see SAPNote 2525644 for more details) /
[Request Info: Object Name = "<owner>"."<object>", FM Name = TREX_DBS_AGGREGATE] Message No. DBMAN099

SAP BW/4HANA

data load , KBA , BW4-DM-DTP , ABAP Orchestration of Data Transfer Process , Problem