Dear Sir or Madam,
Further to my last, I can confirm that COMDLG.OCX exists in the ultralibrarian folder, and I have managed to fix the problem by running the following command (mine is a 64-bit system).
regsvr32 C:\ultralibrarian\comdlg32.ocx
which registered the OCX... You may need to note this in your installation instructions; if it is already mentioned, it is not obvious.
Please feel free to post this or not if you feel that it is useful.
Many thanks,
VM
