If you use a DataFlex version before DF19.1, then you have to add the following line before including the cComAntView.pkg file:
#IF (!@ < 191) Define OLE_VT_UI8 for 21 // 8-byte unsigned int #ENDIF
The reasons for that is because DAW only added that declaration line to their Variants.pkg file in DataFlex 19.1. You can use it before that time as it is an existing Windows variant type. It is only the declaration itself that was missing.