I keep getting these fatal errors:

Fatal error: Allowed memory size of 33554432 bytes exhausted (tried to allocate 791753 bytes) in /home/liabelle/public_html/wp-includes/functions.php on line 805

Fatal error: Allowed memory size of 33554432 bytes exhausted (tried to allocate 7680 bytes) in /home/liabelle/public_html/wp-includes/kses.php(1005) : runtime-created function on line 1

They usually "fix" themself and disappear but they always keep coming back.

- what do they mean?
- must I really do something about them, if yes then how?
- is there any permanent solution for it?

Please help!

Looks like you're running out of PHP memory. You can ask your host to increase it from currently 32 MB to 40, 50 or something. I remember one user had this and his host, although a budget host (I think bluehost or dreamhost?) actually did it and increased to 60 MB

BTW, Atahualpa does not use huge amounts of memory. Do you have many plugins installed, or a very big blog with many posts and pages? 32 MB should be sufficient for WP, Atahualpa and 20 plugins. My server is also set to 32 MB