That dialog indicates that WHS either had problems loading your add-in, or your add-in crashed the console the last time it was opened. The functionality was added to WHS to prevent badly-written add-ins from continuously crashing the console.
If you're debugging, you'll need to select the option to open the console with your DLL.
If you're not sure why your add-in is crashing, check out the HomeServerConsole.xxx.log file that corresponds to the crashes in c:\documents and settings\all users\application data\microsoft\windows home server\logs\ (sort by date, the xxxx is a date/time stamp). You'll see any exceptions logged there.
Tentacle Blog:
http://www.tentaclesoftware.com/blog/
WHS Disk Management:
http://www.tentaclesoftware.com/WHSDiskManagement/