I'm studying windows debugging and as reference I have purchase Advanced Windows Debugging by Mario Hewardt and Daniel Pravat.

Recently I have been stuck on the chapter dealing with inter-process communication. 

Basically there is a com server and a com client. When executing the client I get a CoCreateInstanceEx failure.

How can I determine why this is failing?

Below is a small extract from a procmon capture.  Do you think this is the cause?

10:43:22.1874811 PM 08comsrv.exe 1288 RegOpenKey HKCR\CLSID SUCCESS Desired Access: Maximum Allowed
10:43:22.1876172 PM 08comsrv.exe 1288 RegOpenKey HKCR\CLSID SUCCESS Desired Access: Maximum Allowed
10:43:22.1881439 PM 08comsrv.exe 1288 RegOpenKey HKCU\Software\Classes\CLSID\{31810948-8D81-4E55-BD16-0C27F5629392} NAME NOT FOUND Desired Access: Read
10:43:22.1881546 PM 08comsrv.exe 1288 RegOpenKey HKCR\CLSID\{31810948-8D81-4E55-BD16-0C27F5629392} NAME NOT FOUND Desired Access: Read
10:43:31.8148826 PM 08cli.exe 1856 RegOpenKey HKCR\CLSID SUCCESS Desired Access: Maximum Allowed
10:43:31.8150293 PM 08cli.exe 1856 RegOpenKey HKCR\CLSID SUCCESS Desired Access: Maximum Allowed
10:43:31.8155631 PM 08cli.exe 1856 RegOpenKey HKCU\Software\Classes\CLSID\{31810948-8D81-4E55-BD16-0C27F5629392} NAME NOT FOUND Desired Access: Read
10:43:31.8155737 PM 08cli.exe 1856 RegOpenKey HKCR\CLSID\{31810948-8D81-4E55-BD16-0C27F5629392} NAME NOT FOUND Desired Access: Read
10:43:31.8218332 PM 08cli.exe 1856 RegCloseKey HKCR\CLSID SUCCESS 
10:43:31.8219309 PM 08cli.exe 1856 RegCloseKey HKCR\CLSID SUCCESS 
10:43:37.8175956 PM 08comsrv.exe 1288 RegCloseKey HKCR\CLSID SUCCESS 
10:43:37.8176934 PM 08comsrv.exe 1288 RegCloseKey HKCR\CLSID SUCCESS