Adminer 3.3.3 repoorts "syntax error" on large dumps (created with same adminer 3.3.3).
Same time mysql native client can restore them using "source" command
Some information about this problem can be found here: http://forums.mysql.com/read.php?104,145923,145923
A related bug has been fixed in Adminer 3.3.4. Can you try that version? If the bug persist then you can fill a bug report. Also attaching a dump which reproduces this problem will be extremely helpful.