>While compiling cdo2000.prg an error occurs. Fox version is 6. Maybe cdo200 requires later version of vfp?

It uses Collection class, that is not present in VFP6, to store errors. You can easily change the class to use arrays instead or you can create your own collection class. I provided below a simple implementation of such class for this specific case only.

	PROTECTED PROCEDURE Init
		* Create error collection
		*This.oErrors = CREATEOBJECT("Collection")
		This.oErrors = NEWOBJECT("Collection", "Collection4Vfp6.fxp")

* Collection4Vfp6.prg
DEFINE CLASS Collection AS Custom
	Name = "Collection"
	DIMENSION aCollection[1]
	Count = 0
	
	FUNCTION Add(tvValue)
		This.Count = This.Count + 1 
		DIMENSION This.aCollection[This.Count]
		This.aCollection[This.Count] = tvValue
	ENDFUNC
	
	FUNCTION Remove(tnIndex)
		DIMENSION This.aCollection[1]
		This.Count = 0	
	ENDFUNC

	FUNCTION Item(tnIndex)
		RETURN This.aCollection[tnIndex]
	ENDFUNC

ENDDEFINE