CX_SY_CONVERSION_NO_NUMBER if format is set to 1 234 567,89.

If the decimal representation in the user settings is set to "1 234 567,89" and the BOM is created with an RFC call, the error message CX_SY_CONVERSION_NO_NUMBER is displayed. This behaviour of SAP is incorrect and can be resolved by the following SAP note:

SAP - Note → 1124584