tok tok 🙂
1st - most of php "upload" things use default php.ini setting where post wont accept data > 2MB. you can easily override that with ini_set.
2nd - upload limit/size is usually set to 8MB... again, ini_set if you need to upload bigger chunks.
i know phpmyadmin problems when doing backups & restores. never works well.
go to shell [telnet] and do mysqldump. fantastic thing...
mysqldump database_name > mydump.txt
and here you have your DB dump. now just gzip it and you get mydump.txt.gz... thats your backup. when you want to restore, unzip and do:
mysql database_name < mydump.txt
simple, ha?
check mysqldump options. i usually add --add-drop-table -c [complete inserts]... something like that.
if you need more help, ask! 😉