Hi Chaitanya
The error is because of the first input to useOneAsMany having more than one context. The functionality of useOneAsMany is to take the value from first input (expected one value) and repeat as many times as the second input (should be in one context) and put in the context of third input (should have equal value as second input). Please verify your input to use one as many.
Trace - Too many values in the first queue in function useOneAsMany. It must have the same number of contexts as the second queue] in class com.sap.aii.mappingtool.flib7.NodeFunctions method useOneAsMan.
regards,
Harish