misleading corrupted file warning

[Haroldo Mauro]

My Revolution Studio 3.5 will not open its own stacks except for the first one. If I want to open a second stack or, if I close the 
the one that's runing and try to open it again, I get this message: "Unable to open stack: stack is corrupted, check up for~backup file".
Aparently the stacks are not corrupted, for if I quit Revolution it will open any stack again. So, for every stack I want opened, I need to quit and relaunch Revolution. (Macbook Pro, Lion) Thanks in advance for any help.

Harold