Errors when installing updates (CS5)

I don't think software updates are your problem.  As Jon said, nothing has changed in legacy CS5 in ages.  And most of the updates were for things like Browser Lab service which doesn't exist anymore. 

Try uploading to your remote server with free FileZilla S/FTP client.  It's modern and updated with the latest security patches which CS5 is sorely lacking due to its advanced age. 

https://filezilla-project.org

Failing that, contact your web host.

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The web has changed a lot in 11 years.

TUTORIALS:

- https://www.w3schools.com/html/
- https://www.w3schools.com/css/
- https://www.w3schools.com/js/

MODERN CODE EDITORS:
-- Adobe Dreamweaver CC - https://www.adobe.com/products/dreamweaver.html
-- Atom (free) - https://atom.io/
-- Codespaces (free, browser-based) - https://github.com/features/codespaces
-- Nova (Mac only, formerly called Coda) - https://nova.app/
-- Pinegrow - https://pinegrow.com/
-- Sublime Text - http://www.sublimetext.com/
-- Visual Studio Code (free) - https://code.visualstudio.com/

Have you called you hosting company to verify nothing changed on their end?

Certain companies, like GoDaddy, frequently lose FTP log-in credentials when they update the server.

Since DW CS5 hasn't changed since about 2010, it's unlikely that there's something suddenly wrong with the software itself.