I know that there are many different reasons why you would be getting this error, but I wanted to document one way you can try to get the BTAHL7 DASM:

Error happened in body during parsing
Error # 1
Segment Id: GT1_Guarantor
Sequence Number: 1
Field Number: 51
Error Number: 102
Error Description: Data type error
Encoding System: HL7nnnn

The data looks like this:

|^NOT EMPLOYED|

The first sub element needs to be set to a max of 0 instead of blank (default 1)

As I discover other fixes I will update this entry