I came up with these routines for getting the path to the current project's .dvb file and also to extract just the path from a full path and filename, for AutoCAD VBA. I split this into separate functions because I thought that the GetPathFromFilename function could be useful in other places. I hope others find these useful.
Public Function App_Path() As String
'Works like app.path in VB
Dim str As String
str = ThisDrawing.Application.VBE.ActiveVBProject.Filename
App_Path = GetPathFromFilename(str)
End Function
Public Function GetPathFromFilename(sFile) As String
Dim arr() As String
arr = Split(sFile, "\", -1, vbTextCompare)
GetPathFromFilename = Left(sFile, Len(sFile) - Len(arr(UBound(arr))))
End Function