$string['contrib:managereviewcriteria'] = 'Manage review criterias for contributed plugins'; - the plural is criteria (no s necessary)
$string['vcssystem_help'] = 'This is the <b>V</b>ersion <b>C</b>ontrol <b>S</b>ystem that you use to track your development efforts on this version of the plugin. Please select the CVS you use or alternativily select other and tell us which one you use.'; - alternatively misspelled
$string['softwareversion_help'] = 'This is the verion number of the software release. In the case of Moodle this is the version number in version.php, in the case of PHP this is just the release number e.g. 5.3.2'; - version misspelled
string['nopluginawards'] = 'This plugin hasn\'t recieved any awards yet'; - received misspelled, also I do not like to see contractions so has not would be preferable to hasn't (IMHO)
$string['externaldocurllink'] = 'More documenation on this plugin can be found at '; - documentation misspelled
in $string['addnewversion_desc'] - Sumbit - Submit misspelled and replace don't with do not (avoid contractions)
In file comments - 'Thie file' should be 'This file'
$string['websiteurl_help'] = 'If you have a website set up that has more information about your plugin or your work you can put it\'s URL here.'; - not a contraction, use its instead of it's or simply 'the URL'.