So today I was tasked with helping a client move an old custom VB6 app to a new Windows 2003 server. The company that created it was asking for an arm and a leg for a simple transfer. After we moved the entire program directory over everything seemed to be fine until we encountered an "ActiveX component can't create object" error. I was perplexed on how to track down the issue. There were not accompanying DLLs or OCX files. I tried Process Explorer to see if I could find any failed openings and the strings contained in the exe.

After some searching on the net I found this lovely page http://www.cryer.co.uk/brian/windows/trbl_nt_axccco.htm . It details on how to use Sysinternals Regmon to track down issues with failed ActiveX creation. Basicall you watch your program for registery key openings and look for any failed opens in the HKCR/Classes path. After running the program and encountering the error I found it.
HCKR\Classes\cdonts

When I saw that come up I immediately knew what to do. cdonts is no longer included with windows server. It is an emailing library using cdo. I've had to install it on new Windows 2003 servers more than once so old ASP classic sites could run. All I needed to do after figuring it out was copy the cdonts.dll over to the C:\windows\system32\ directory and run regsvr32 on it. Everything was golden.

I've been using Sysinternals for years. I'm always amazed at what new ways I can use their utilities to track down issues. Process Explorer has been a godsend for me over the years. After discovering it, removing malware from computers took me less than half the time it used to. It gives me so much information I'm not sure how I got by without it.

The Sysinternals Suite is a must have for any serious windows programmer or administrator. It ranges from programs to monitor network connections to being able to see and suspend individual threads in a program.