to install new filemaker pro 12 is it necessary to uninstall fm-11 pro ?? :grad:

No. They can both be opened simultaneously because they have different file structure. :^)

As LaRetta says, you can open multiple copies of FileMaker. However the only restrictions that I'm aware of are that each app has to have its own serial number, and that your operating system supports it, i.e Lion and v6. I often have 3 or 4 FileMaker apps opened at the same time depending on what I'm working on.