Prject cannot restore to CitectScada 6.10

[deepforest8023]

When I was trying to restore one project to CitectScada 6.10, it came out one dialog says: cannot convert xxx to version 6.xx format. you must use version 5.31 or greater to convert this project before upgrating!!! but the software in my laptop is same version with it the project was backed up before.
can some one help me to analyse how to resolve the problem.

thanks in advanced.