Some of our Enterprise Portal links which points to SSRS reports were not getting saved when we input it through "Manage Links" option when you edit the page via Sharepoint
For e.g. one of the link which gives the problem was http://servername/Reports/Pages/Report.aspx?ItemPath=%2fMAX+Reports%2fPromotions+Claims+Report+Rebates
When saved, it spits out an error saying "The URL Property is not well formed"
Replace the “+” character with “%20” (which is used for space) and that works like a charm!