Runtime error while executing 'CUSTOMER_CLEARING' function module

Hi Experts,

When I execute fm 'CUSTOMER_CLEARING', I get a run time error that says that there is a type mismatch with respect to

'I_MODE' parameter used. This dump occurs when there is a call to fm 'POSTING_INTERFACE_START' by this fm. I tried executing it with different values for 'I_MODE' ,such as 'A', 'S', 'E' etc but every time it gave a run time error.

Kindly suggest what might have gone wrong.

Thanks in advance,

Regards,

Puja