500 internal server error on both wp and my OS commerce shop on uploading

OK – this sounds really odd but on the first stage of installation, ie uploading the folder to the wp-content/plugins folder, my wordpress site crashes completely – the site just comes up with an 500 server error message (see bottom of this post for that). Rather more worrying, my other database-driven site on my webspace, an OS Commerce installation, also returns the same error. The only way to recover the functionality of both sites is (it seems) is to remove the google analytics plugin folder from the plugins directory and then wait two minutes for the sites to start working again.

I totally don’t understand this – because I haven’t configured anything, I’ve just uploaded a folder. None of my other sites or online files are affected, just the database sites.

I tried removing unused wp plugins, and deleting the folders, and then reuploading the plugin folder. Three times, it did the same thing to both my sites, so now removed.

Using linux / apache servers (1&1 internet), upload via Filezilla

OK I’m not totally technically competent but I really don’t understand this one.

Internal Server Error

The server encountered an internal error or misconfiguration and was unable to complete your request.

Please contact the server administrator, and inform them of the time the error occurred, and anything you might have done that may have caused the error.

More information about this error may be available in the server error log.

Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.

https://www.ads-software.com/plugins/google-analytics-dashboard-for-wp/