"Posting key not Defined" error after adding custom fields in MIRO header.

Hello experts,

I added some custom fields in MIRO header,under basic data tab.Fields are coming at MIRO screen.

but if we see previous invoice or create new one it is giving an error like "POSTING KEY NOT DEFINED".

i searched it out but get nothing. Please give your valuable suggestion.

Thanks in advance.

Ashwani