Hello Christian,
So VComponents installed separately from the application, right? Yes, that can be the problem - the versions of plugin and VComponents need to be the same.
It can be checked in the Terminal.app, for example:
$ otool -L "/Users/sergey/Paradigma Software/V4RB_9/Examples/VReport/GeneralOnSQLite/My Application . debug . app/Contents/Frameworks/v4rb_cocoa.dylib"
Output:
/Users/sergey/Paradigma Software/V4RB_9/Examples/VReport/GeneralOnSQLite/My Application . debug . app/Contents/Frameworks/v4rb_cocoa.dylib:
/usr/local/lib/v4rb_cocoa.dylib (compatibility version 9.1.1, current version 9.1.1)
/System/Library/Frameworks/CoreFoundation.framework/Versions/A/CoreFoundation (compatibility version 150.0.0, current version 635.21.0)
/System/Library/Frameworks/CoreServices.framework/Versions/A/CoreServices (compatibility version 1.0.0, current version 53.0.0)
/System/Library/Frameworks/ApplicationServices.framework/Versions/A/ApplicationServices (compatibility version 1.0.0, current version 41.0.0)
/usr/local/lib/vcomponents/libvshared_fat_release.dylib (compatibility version 9.1.1, current version 9.1.1)
/usr/local/lib/vcomponents/libvkernel_fat_release.dylib (compatibility version 9.1.1, current version 9.1.1)
/usr/local/lib/vcomponents/libvclient_fat_release.dylib (compatibility version 9.1.1, current version 9.1.1)
/usr/local/lib/vcomponents/libvreport_fat_release.dylib (compatibility version 9.1.1, current version 9.1.1)
/usr/lib/libc++.1.dylib (compatibility version 1.0.0, current version 28.1.0)
/usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 159.1.0)
The version is 9.1.1.
For deployment, it is better to copy VComponents to the application bundle, so the version will be always the same.
As for the server version, usually it doesn't require to be exactly the same but versions 8.x and 9.x use a different protocol, so a client must be upgraded to work with 9.x VServer.