Blocks are not exactly intelligent when going from one project to another. If a block is associated with an object in a file and you want to use it in another project it will lose the association and you will need to re-associate it to the object.
This tag on the left, for example is suppose to pull the rooms area based off of a polyline that is outlining the room. As you can see the tag is showing the pound symbol instead of the square foot area. The tag on the right is showing correctly.
How to re-associate a block tag with Attributes:
This can be done by inserting the block into the drawing. Then double click on the block to open the "Enhanced Attribute Editor". Select on the attribute tag that you want to modify. Delete the content in the Value and then right clicking and select "Inserting Field".
In the Field dialog box set the field category to "Objects" and the field names to "Object" click on the select object icon in the next column so you can select the object in the drawing to associate the tag. Set the property for this example Area was select. You can also set up the format and precision. Click the OK button to go back to the drawing to see the updated tag.