obj.ExportEx path from variable

[#1]

Trying to build a sub that exports a chart to an Excel file, where the user can choose the name and path to said file.

I have the following code (VBScript):

sub ExportToExcel()
                dfltWy = ActiveDocument.Variables("Default_Path").GetContent.String
                    dfltNm = ActiveDocument.Variables("Default_FileName").GetContent.String
                           pthWy =inputBox("Choose Path",,dfltWy)
                            flNm = inputBox("Choose Name",,dfltNm)
                     ActiveDocument.Variables("Path").SetContent pthWy, true
                     ActiveDocument.Variables("File_Name").SetContent flNm, true
                     expPth = chr(34)&pthWy&flNm&chr(34)
                     MsgBox(expPth)
                            set obj = ActiveDocument.GetSheetObject("CH07")
                     obj.ExportEx  expPth, 5           'it works fine 'til here. The MsgBox displays the correct path "C:\User\QlikView\Project\Default.xls"
                                                                           '(including quotations), but no file is created. 
        '            obj.ExportEx  "C:\User\QlikView\Project\Default.xls", 5      ' <-<-<- this works as a check  
end sub

Any ideas on how I can get the obj.ExportEx to export according to the expPt variable?

[#2]

Solved it by switching tactics. Ended up with something similar to [the end of] Jacob Berglund's solution on:

http://qlikcommunity.qliktech.com/thread/7593

Would still be interested in whether it is possible to use obj.ExportEx for this...