BPC 10 "SAVE DATA" ERROR

Hi gurus,

When any user try to save data from input forms, we got this error : "There was an error deserializing the object of type FPMXLClient.BPCProxy.MetaData_Data.InputResponse. Encountered invalid character '"

It states that saving data is unsucessful. However, the data is sent to BPC cubes when i check from BW.

PS: we recently migrated the system from 7.5 to 10 and all the reports are rebuilded.

Thanks in advance,