Hi Dagmara,
good to hear that you were able to install the HotPot module on your Moodle 2.3 site. Well done.
The message you got says that you do not have the minimum version of the "report_completion" plugin that is required by the "completionstatus" block.
I don't know much about either of those plugins, except to say that they are both standard plugins and they have nothing to to do with the HotPot module.
The two files you need to check are:
- blocks/completionstatus/version.php
- report/completion/version.php
If you continue to have problems, please post to the "Installation problems" forum, or create an issue on the Moodle issue tracker.
regards
Gordon