This is a result of a new security feature in the Blackbaud NetCommunity 6.53 version.  This new version of Blackbaud NetCommunity has added a new task right called "File tasks" to the Task Groups.   By default this new file tasks is not enabled for any task group and therefore user are not able to see the "From Files" tab when creating links.  In order to allow users to view this tab your site administrator will need to do the following: 
 
1) Select "Task Groups" from the "Users & Security" menu
2) Edit a Site Task group from the list 
3) Scroll until you see "File Tasks" 
4) Assign the desired File tasks rights to the task group by selecting the check box
5) Select Save 
6) Repeat for any task group you desire to have File Task rights