Hi Rohit,
I'm not sure what the desired output is in your form, but to fix the error you saw in Collect simply take out all skip logic conditions that refer to the question "What are primary, secondary and tertiary treatment stages of the system? Specify further details about component in the below provided text field." ('What_are_primary_secondary_an_') -- you have several question refer to this question.
Alternatively, you could not use a repeat group and instead add three sets of questions for primary, secondary, and tertiary treatment stages and build your skip logic so that it works with one or all of these three variations of the same question.
Best,
Tino