im telling you that you havent uploaded it to where it needs to be -- I have a pretty good idea what you are doing wrong - but before I explain, we are going to let go of the "ive been doing this a long time" feeling, and put on our thinking caps..
Here is where your sociable plugin is installed to:
http://www.susiej.com/wordpress/wp-content/plugins/social_bookmarks/
See that 403 forbidden? That tells me that that directory exists, BUT that it does NOT have an index.php in it, and that your server is set up to not allow browsing unless an index file exists within a directory.
Thats called having Options All -Indexes turned on, btw.
Now, lets look at this again:
http://www.susiej.com/wordpress/wp-content/plugins/wp-phpmyadmin/
Thats clearly a NOT FOUND. Its not there, period, and if it were, you would see it on your plugins page. :)
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Now, as to what you are doing, what is the path you are uploading to? what PATH do you see in your ftp application?