I patched tgm-activation.php (solution found on Google) :
In my theme, replaced this line :
if ( ! function_exists( ‘ultimate-soccer’ ) )
by this one :
if ( ! function_exists( ‘tgmpa’ ) )
So the error about “Cannot redeclare tgmpa()” is gone and now I can successfully activate your plugin 🙂
However even activated I don’t see any “WP Posts Show Pro” entry in the dashboard menu 🙁