Hello,

It seems you have other issues too on your site, and some not well installed other extension (nonumber ones for example...)

I would first recommand you to try to update iCagenda using the Joomla Extensions manager.
If still issue, then check all permissions on files and folders on your Joomla repository (could be only a few one files with permissions issues).
Then clear the temp folder.
And try again using Joomla updater for extensions.

Hope this helps in a way, but seems other issues there...

Regards,
Cyril