You are calling the PerformUnroll method with the wrong arguments… it has to be 3 “out” parameters which you can assign to dummy variables.
http://developer.rhino3d.com/5/api/RhinoCommonWin/html/M_Rhino_Geometry_Unroller_PerformUnroll.htm
Also, you may be confused about the difference between VB.Net in Grasshopper and VBscript in Rhino, they are two completely different languages.
Maybe have a look at the rhinoscriptsyntax module in Python, there is a UnrollSurface function you can call directly.
http://developer.rhino3d.com/api/RhinoScriptSyntax/#collapse-UnrollSurface
You’ll have to upload a .gh file with the specific problem if you want any more help, read this: