Can't delete any plugins

Hi… recently switched our site URL address using an add-on domain. All is running smoothly with the exception that we can no longer delete plug-ins listed in the WordPress Console. I can add and update plugins. But cannot delete any. When I open Firebug in the console, I get a long list of errors:

[09:58:24.462] Use of Mutation Events is deprecated. Use MutationObserver instead.
[09:58:24.605] Unknown property ‘box-sizing’. Declaration dropped.
[09:58:24.605] Error in parsing value for ‘background-image’. Declaration dropped.
[09:58:24.606] Unknown pseudo-class or pseudo-element ‘-webkit-input-placeholder’. Ruleset ignored due to bad selector.
[09:58:24.606] Expected media feature name but found ‘-o-min-device-pixel-ratio’.
[09:58:24.606] Expected media feature name but found ‘-webkit-min-device-pixel-ratio’.
[09:58:24.607] Unknown property ‘box-sizing’.
[09:58:24.607] Unknown pseudo-class or pseudo-element ‘-webkit-search-decoration’. Ruleset ignored due to bad selector.
[09:58:24.608] Unknown property ‘user-select’. Declaration dropped.
[09:58:24.608] Error in parsing value for ‘filter’. Declaration dropped.
[09:58:24.611] Error in parsing value for ‘background-image’. Declaration dropped.
[09:58:24.615] Error in parsing value for ‘text-shadow’. Declaration dropped.
[09:58:24.616] Expected media feature name but found ‘-o-min-device-pixel-ratio’.
[09:58:24.616] Expected media feature name but found ‘-webkit-min-device-pixel-ratio’.
[09:58:24.616] Unknown property ‘box-sizing’. Declaration dropped.
[09:58:24.616] Error in parsing value for ‘background-image’. Declaration dropped.
……
[09:58:46.082] The Web Console logging API (console.log, console.info, console.warn, console.error) has been disabled by a script on this page.

Any ideas on how to correct this situation?

Thanks in advance. Mike