I have deployed FBA pack to a SharePoint site successfully but while adding web-part to page it shows error as in below image..
What has to be done now to solve it?
Check Farm Solutions in Central Admin and make sure that the FBA Pack shows as deployed to the web application you're getting the error on. Even if it shows that it is, try undeploying and redeploying to the web application. If that doesn't work, try Deactivating and Reactivating the Site Collection feature.