The Telnet protocol handler is disabled by default in Microsoft Internet Explorer 7. In order to use the Telnet tool in WhatsUp Gold, you need to re-enable the Telnet protocol.
To re-enable the Telnet protocol:
Regedit, then click OK. The Registry Editor opens.HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\Main\FeatureControl
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\Main\FeatureControl, create a new key named FEATURE_DISABLE_TELNET_PROTOCOL.DWORD value named iexplore.exe and set the value to 0 (decimal).