Plugin Installer & Admin Widgets not working after moving URL

I have just built a new WP site and moved it to a new URL. I found lots of great info on moving to a new URL and followed steps (mostly changed wp-options URLs in phpMyAdmin). Fantastic.
Still have some remaining issues, which I assume are related to moving the URL.
1- My Plugin Installer does not install plugins anymore, so I am doing this manually. I would like to understand how to fix it, though!
2- On WP Dashboard, the Widgets don’t work for WP News, Google Analytics (plugin that I installed), etc. I’m assuming that something is wrong in the permissions or setup somewhere.
I think these can be resolved by changing permissions to a file but I have tried a few times without success. (I tried changing permissions for .htaccess and the uploads folder so that groups could write.)
A thousand thanks to anyone who can help!