Problem opening files with TB 10

Hi, (sorry for the English Language)
this morning I opened a file TB10 clicking on the program, and I appeared this notice:
"Coul not load required system book: C: \ Program files (x86) \
ToolBook\ToolBook 10 \ tb100xml.sbk"
I checked the folder and the file is tb100xml.sbk (folder Toolbook 10).
Can anyone help me?
(I attach image error
Carlo (Italy)
this morning I opened a file TB10 clicking on the program, and I appeared this notice:
"Coul not load required system book: C: \ Program files (x86) \
ToolBook\ToolBook 10 \ tb100xml.sbk"
I checked the folder and the file is tb100xml.sbk (folder Toolbook 10).
Can anyone help me?
(I attach image error
Carlo (Italy)