common dialog with WinXP behaving inconsistently

[jpcw]

I have developed a HTA application which uses the common dialog control ActiveX component (comdlg32) to perform open and save file specification operations. The control is embedded in an OBJECT tag, and a separate License Pack (.lpk) object is referenced to allow runtime use of the control. This works on most machines that the app has been tried on (mostly tested on Win 2000 professional), but on some XP machines, it fails. One possible link that has been identified, though not proved, is that the XP machines that the HTA does work on also have Visio 2000 installed. Can anyone suggest any other possible causes, and preferably remedies? As a workaround, I've leveraged the open/save dialog from MS Excel instead (all the machines using the HTA have this), but it's kludgy and is prone to large orphan processes springing up.