I’m getting a similar problem. I’m running Windows XP (SP3). After installing gpg4win 2.0.4 I found I did not have WinPT, so I downloaded it.
When I run WinPT, up pops the dialog “Could not find the GPG binary (gpg.exe). Do you want to start the GPG preferences to correct this problem?”. I click “Yes”.
Next I get an error message saying “The procedure entry point WNetEnumCachedPasswords could not be located in the dynamic link library MPR.dll”. I click “OK”.
Now I get the GnuPG preferences dialog. I click “Browse” and navigate to C:\Program Files\GNU\GnuPG\pub\gpg.exe", then click “OK”.
The response is an error message: “Invalid crypto engine”. I click “OK” and the WinPT software ends.
Any advice much appreciated!