try with this, that's the basics :
check the file size, if its nil, or abnormally big, it could mean that the file is simply corrupted
after that, log on mysql, and type
use eq;
show tables;
check if you see account in the list of the tables.
if you see it :
show columns from account;
compare the returned structure with a valid one (find it in a recent sql.db).
this should alllow you to check the integrity of your table, post back for more help once done...
Burthold posted a link where he described the database schema :
http://www.rpg-forums.com/eq_44.htm#account,