There is a 99.9% chance this is because of incorrect permissions. CHMOD all executable PHP files to 644 (if you have PHPSuExec or similar installed, all quality webhosts do so just try it) and also ALL folders to 755. /tmp and /media however may need to be 777 for max compatibility.
Try installing another extension apart from JoomlaComment on your localhost, then use JoomlaPack to transfer to livesite - same thing will happen.
You need to use one of the certain modes in JoomlaPack to restore your backup correctly if copying from a Windows/OSX -> Linux server, but I can't remember which. And there is a bug in my version. I have not used it for a long time but thanks for reminding me to talk to them about it