Try this

1) Find the header() statement that is causing the problem. The error must be at or before this line.

2) Look for any statements that could send output to the user before this header statement. If you find one or more, change your code to move the header statement before them. Complex conditional statements may complicate the issue, but they may also help solve the problem. Consider a conditional expression at the top of the PHP script that determines the header value as early as possible and sets it there.

3) Make sure there is no white space outside of the php start and end tags. While a blank line before the <?php start tag may look innocent, when processed by PHP, it will turn into an echo statement printing out a blank line. This is a common culprit.

Try use a default WP theme to test.. if that works then you have made some change to the theme you are trying to use...and its got some errors. If what getsometraffic has suggested is too hard for you, then reinstall the theme from scratch. Your data wont be lost as it is all stored in database.

It seems its not just your admin page, it is the whole site really that has a problem..

First of all check file which is showed in error:
wp-content/themes/Appland/functions.php

Error tell you than in this fine in line 2 there is some code which send something to browser (it can be whitespace or something other). After that other code which try to send header to browser can't do it because already something is sent in that functions.php file.

So your theme made all that problem and whole site not works. You will not login now to admin. You need to connect to server by FTP, download functions.php and check its content to see what wrong is there. Fix file and upload to server.

If you can't fix file yourself than post here few first lines so we will check it.

Tom

Use ftp to rename wp-content/themes/Appland/style.css to something like

wp-content/themes/Appland/style.bak

Then you will at least be able to load the site,

You might try uploading the Appland theme again or getting a theme that's not broken.

all this stuff just went right over my head. lol

Can anyone of you sort it out for me? I don't have a clue how to do this.

I really don't know how this has happened. it was fine the last time I was on it on the 14th of this month, then BOOM!!!! this happens.

I can get into my cpanel, so if anyone wants a look please, let me know and I can pm you my login.

If few days ago site was fine and you did not do any work on templates than your site could be hacked and maybe some bad code was added to your theme files. You need to check that too and install some security plugins if you don't have any yet.

Tom