value was either too large or too small for an int32

Not sure if I am right here, but I have no idea where else to go after my support request was rejected.
I can never open IDML files in Trados 2015.
I tried your workarounds for opening idml files but it does not work for me at all.
I have attached the file, I tried the setting to "Process unsupported formats" in the Common section. No luck.
Any tips?
I get the following error message when I try: "value was either too large or too small for an int32"