One thing you can try is.
1. Click on Settings->Interface->Show Types in Templates
2. Click on Templates -> Types and find the Item that is name "All" (it will have a star as it's icon)
3. Delete that item.
4. Reinstall planswift here is the link to the latest version http://www.planswift.com/download/?v=9.1
5. The re install -> will re-add that type back into the types folder.
6. Try the dimension tool again and see if you get the error.
This this item contains a the type for the dimension tool. when you install planswift if the item exist planswift will not overwrite it. It could be that this file is from an older version of the software.
let us know what the outcome is.