Importing .sql file replaces special characters (á, ç etc.) with questions marks

[helil]

I am trying to import an .sql file into a new instalation, but the resultant table replaces special characters (á, ç etc.) with questions marks.
Editing entries manually via PhpMyAdmin doesn't work either.

Destination versions:
phpMyAdmin 2.6.1
MySQL 4.1.9-max

Thanks in advance