SQL & PL/SQL

Hi, i am looking for some help in regards to import data into a new table. I have 3 columns with date and times and when importing I am changing the data type as DATE with the format specified as DD/MON/RR HH24:MI:SS (options in preference for NLS are set the same) and the size set at 255. This verifies all ok and When I finish this than I get the following error:

insert failed for row 1 time GDK-05043 not a valid month

I then changed the datatype to TIMESTAMP DD-with the format MON-RR HH24.MI.SSXFF but this still gives me the same error.

When I import with the datatype set as VARCHAR2 then this imports all the data.

An example of a date and time value from the csv is the following:

01/12/2012 22:51:57

If somebody could please help me fix this as ideally want these as date and time values in their tables. Thanks in advance.