View Problem with joins (no replies)

Hy, I have this problem.

Informix

select *
from
outer(ref x0 ) ,en x1 ,enc x2
where (((x1.p = x0.c ) AND (x1.n = x2.n) ) AND (x2.c = x0.c ) ) ;

And in mysql, I'm doing

from enc x2, en x1 left join (ref x0)
on ((x1.p = x0.c) AND (x1.n = x2.n) AND (x2.c = x0.c)))

but this sentence give me this error:

Error Code : 1054
Unknown column 'x2.num' in 'on clause'
(10 ms taken)

How I can do this right.
Sorry, for my poor english.