You are absolutely right marcov,
I found the dependency. It comes from the FastReport package that uses zlib1.dll.
The laptop computer running win 7 has already the zlib1.dll but this one needs libgcc_s_sjlj-1.dll (I didn't use a dependency walker but the app works when I replaced this dll with the one on the dev machine).
So I will include the correct zlib1.dll in the installer...
Thanks for all.
PS if someone has an answer
Are all packages included in an application rebuilt with the correct build mode when App build mode is set to release (even if "generate debug info" is set in packages option) ?