Error: Tap failed to load (E0051)  
 
Description: The "tap driver" is an intermediate NDIS driver. EnterNet uses this driver to communicate with the Microsoft Networking stack. This error message generally occurs when internal networking conflicts arise.  
 
Possible Resolution:  
 
Upgrading to the latest version will alleviate most cases of this error.  
On Win2000 or XP operating systems, there is usually no need to reboot after installing EnterNet, as long as you stay logged on with administrator priviledge. If you log off and log in as a non-administrator priviledge however, you will get this error. Shutting down and restarting the system will work around this error.  
EnterNet has two different "tap" drivers built into the software: Filter Driver and Protocol Driver. In some cases you may need to change to using the Protocol Driver, under the advanced settings control box.  
This has been found to happen on some systems that weren't cleanly uninstalled. Uninstall EnterNet, delete any Efficient Networks or EnterNet directories, and then re-install EnterNet. If that still does not fix the problem uninstall everything again and uninstall and re-install the network adapter EnterNet binds to.  
If all else fails click here.