File open issue in MSP2013 Importing XL Data

Hi Folks Im very new to this so Im sorry if my question seems lame, I have used search and I just cant get past this issue

In 07 I do not have any issues but in 2013 I cant seem to get the file open dialog box, choose a file and have the macro continue to impoort thre data unless I specify the exact path.

Im sending the import map to the global
Then Im opening a specified file and importing data
Im then deleting the map from the global

This all works well if I specify the name and location of the file.

OrganizerMoveItem Type:=7, FileName:=ActiveProject.FullName, ToFileName:="Global.MPT", Name:="Map1"
  FileOpenEx Name:="C:\Users\Office\Desktop\Testimportdata.xls", ReadOnly:=False, Merge:=1, FormatID:="MSProject.XLS5", map:="Map1"
OrganizerDeleteItem Type:=7, FileName:="Global.MPT", Name:="Map1"

If I want to choose a file I have altered the code like this (which works in 2007)

FileOpen , ReadOnly:=False, Merge:=1, FormatID:="MSProject.XLS5", map:="Map1"

However in 2013 It fails to go to the open dialog box and I dont get to choose a file for importing, This happens whether I use FileOpenEx or FileOpen

Any advice would be greatly appreciated -

Thanks

JB