I assume you're using Oracle 9i or earlier, because it can only reference a column from a table referred to in the parent statement. Not two levels up. (From version 10 and forward it's unlimited.
I would suggest you use a join instead of a subquery.
Like something similar to this
SELECT l.ID_JALURPOHON "ID Jalur Pohon",
l.ID_RUASJALAN
|| ' - '
|| (SELECT N.NAMA_PANJANG
FROM NAMA_JALAN N
WHERE L.ID_RUASJALAN = N.ID_NAMAJALAN)"Nama Jalan",
m.da "Tanggal Perabasan"
FROM APOHON L, ( SELECT ADD_MONTHS (D.TGL_PERABASAN, J.PERIODE_RABAS) da,
d.ID_JALURPOHON
FROM ADETIL_POHON D, Jenis_POHON J
WHERE d.ID_JENISPOHON = j.ID_JENISPOHON
ORDER BY da ASC) M
WHERE ROWNUM <= 1
AND m.ID_JALURPOHON = l.ID_JALURPOHON