Can't access the admin area

[papergirl +]

For some strange reason on my website running v4.1.3 designer i cannot access the admin area as i get these errors.

Notice: Query failed: MySQL server has gone away SQL: SELECT oTotal FROM class_orders WHERE oStatus=1 AND oDate >"2009-07-01" AND oDate<"2009-07-31 23:59:59" in /home/sportpon/public_html/includes/classes/database/mysql.php on line 143

the front end of the website works fine, the website was working fine for a while and yesterday I just started getting these errors.

the same for my other site running v4.0.9 Designer
Notice: Query failed: MySQL server has gone away SQL: SELECT name, directory FROM class_modules WHERE state=3 ORDER BY mOrder in /home/phhwv/public_html/placements/includes/classes/database/mysql.php on line 140

the front end works fine as well,

I have contacted my host , but they are a bit stumped so I thought I'd see if anyone here might have an idea as to why I'd be getting those errors out of the blue, i.e i haven't touched the files for a few months

I can login but once logged in these errors appear and it runs very slow.