It looks like you have error_reporting turned on. Those deprecated messages are not fatal. They're just telling us there's a spare & (ampersand) where there doesn't need to be one.
You've got a couple of options. The better thing to do is to figure out why you're getting those deprecated messages (do you have WP_DEBUG turned on?) and then relax the error_reporting level. Alternatively, you can edit that PEAR.php file and just take the & off of the two lines (527 & 529).
Those messages are only output actually because you're using PHP Version 4.x. If you're able to upgrade to version 5.x, then those messages will disappear as well.
Lots of options!! Do these things make sense?