For the Windows version of DSLstats there are two DLLs which are included in the downloaded archive - libeay32.dll and ssleay32.dll. Make sure that these are there in the same folder as dslstats.exe. If they are there, you might try temporarily moving them to a different location (or renaming them). This will cause DSLstats to use the installed versions of these DLLs if they exist. If none of this works I'll have to think again.
The reason I think that the problem lies with one of these DLLs is that they are required for TLS emails to work, and this seems to be the most likely reason for the function hanging.
Thanks for the quick reply it sparked the idea which solved the problem
I tried deleting the old 'libeay32.dll and ssleay32.dll' I had in C:\Windows (would be picked up in the PATH for the user) and it did not work.
Solved, Yahoo have two alternative port numbers you can use to access mail (port 587 or 465) if your ISP does not allow port 25.
I use/used port 465 as my old ISP used to filter out port 25 & 587.
Port 465 is now being used by 'Thunderbird' my e-mail program as I have forgotten to change it, everything works OK.
If I use port 465 in DSLstats it does not work and hangs the GUI as reported.
If I change it to port 587 DSLstats works and the test email is sent.
Their appears to be some problem using port 465 when SSL/TLS is selected in DSLstats.
Hope the clue helps you to track the problem.