When using WP3 in a multisite setup and trying to network activate the plugin it will at look fine until you go to any admin page for a site at which point you get the message.
Broken Link Checker installation failed. Try deactivating and then reactivating the plugin.
Installation log follows :
I have found that If you network deactivate the plugin and then activate it per site its fine. Also if its activated then deactivated on a site before its has been network activated it will be fine on that site, but not on other sites.