Troubleshooting

Conflicts with other applications

Skype

Skype seems to take over callto-links all the time

In Skype's Configuration and then Advanced settings the checkbox "associate callto-links with Skype" might be checked. When Skype starts it resets the callto-link to Skype. If you disable this then your application should work again.

Configuration

ODBC

My newly created ODBC-alias doesn't work If you are using 64-bit OS and it's a 32-bit application you must use c:\windows\sysWOW64\odbcad32.exe to configure ODBC-alias. Typically Windows launches C:\Windows\System32\odbcad32.exe. The reason is that the latter creates 64-bit aliases but the other uses 32-bit. Make sure you also have 32-bit driver installed (or 64-bit if that's the case).