is this a 1and1 problem or me?

So I got my database set up in 1and1, and did the necessary adjustments to the wp-config.php file and my wordpress blog is set up and working fine. But I have tried to upload a plug-in and all I get is a “missing temporary folder” message. (issue 1)I put the plug-in file in the wp-content/plugins directory with ftp, but when I try to get wordpress to find it, well firstly everything moves very slowly (issue 2),and then about 50% of the times I get an error message when I click on the plug-in or add plug-in tab (An unexpected error occurred. Something may be wrong with www.remarpro.com or this server’s configuration. If you continue to have problems, please try the support forums.) and other times it works fine,(issue 3). I’m guessing I’m missing some permissions, and I am quite sure it’s all possible from 1and1 (done it for other things) but I’m new here and a bit confused as to where to start. I know html, js and css but am new to php. Any advice apptreciated