External HDD checkdisk problem

i have an external hard drive 80GB , and i make it in two partitions..

my problem is , some folders on the HD when i want to access it i got an error message about curropted directory, i performed the chkdsk utility but when it complete about 98% and says '' could not complete check disk'' .

if anyone could help me , he will be my hero .. and other's hero too.

i am waiting