When opening a pre-10.1 project in ISE 10.1, via Tcl script or through the Project Navigator, I find that the following error message is issued twice:
"ERROR: failed to create Locate Missing Dialog"
This occurs after the message:
"Do you want to update the project?"
The TCL script will fail, but the Project Navigator GUI will allow you to located the missing files.
This issue occurs if there are spaces in the directory name. The work-around is to use the GUI, which will ask you to manually find the missing files.
This problem has been fixed in the latest 10.1 Service Pack available at:
The first service pack containing the fix is 10.1 Service Pack 3.