how to run this query?!!?!?!?!!?!

[readyforwar]

########
# Run Query:
########

ALTER TABLE `df_forum`.`PREFIX_user` ADD `avatar2` TEXT NOT NULL;

Replace “df_forum” with the name of the database where your ‘user’ table is stored
Replace “PREFIX_” with the prefix of your tables, (or just remove it)

################################################## ############################## ####
Done!

i got access to the query thing in the admin cp

and i put this
ALTER TABLE `df_forum`.`PREFIX_user` ADD `avatar2` TEXT NOT NULL;
in the manual and ran it

and now i got database error sent to my email

help!!!!!!!!!!