When I use "regsvr32 foo.dll" i get a "The specified module cannot be found" error.
The error is being caused because regsvr32 cannot find the file even though it is the current folder.
I have specified the full path, and it still doen't work. Any ideas????
This can happen if foo.dll has a depenency on bar.dll and it's actually bar.dll that can't be found.
Try using depends.exe from MSVC to check the dependencies of foo.dll and see if any are missing.
Another option is to download and run FileMon. Then run regsvr32 again and see which file/module it fails to find. This should definitely track it down.
On the 64bit OSes, Dependency Walker has been uninformative for me; and FileMon has been replaced by Process Monitor (see https://learn.microsoft.com/en-us/sysinternals/downloads/procmon to download the utility). Here is how I was able to find the missing references using Process Monitor:
Open the Filter Dialog either from the toolbar or the menu.
Add the Process Name of regsvr32.exe to the filter list and remove any PID filters.
Clear the list, ...
... turn on Capturing, if it is not already on.
Run your regsvr32.exe command from a console window. Once complete, you might want to toggle the capture off.
Look for the missing reference after regsvr32 has loaded your DLL.
In my case REGSVR32 claimed "no file found..." when the DLL's (actually legacy VB OCX's) were in SYSTEM32. After moving them to a another directory REGSVR32 succeeded.
In some versions of Windows10 the file to be registered by SYSWOW64\REGSVR32 has to reside in SYSWOW64