Yeah, long raw isn't used to store text, I just looked it up.
Speak with your dba, or get a new one
CAST does not support LONG, LONG RAW, any of the LOB datatypes, or the Oracle-supplied types.
There may be a means to extract it using a Stored Procedure though, depends on what they've stored int here, if it's text, it might be a text file, which isn't the same as text.
Info on RAW and LONG RAW Datatypes:
The RAW and LONG RAW datatypes store data that is not to be interpreted (that is, not explicitly converted when moving data between different systems) by Oracle Database. These datatypes are intended for binary data or byte strings. For example, you can use LONG RAW to store graphics, sound, documents, or arrays of binary data, for which the interpretation is dependent on the use.
Oracle strongly recommends that you convert LONG RAW columns to binary LOB (BLOB) columns. LOB columns are subject to far fewer restrictions than LONG columns. See TO_LOB for more information.
RAW is a variable-length datatype like VARCHAR2, except that Oracle Net (which connects user sessions to the instance) and the Import and Export utilities do not perform character conversion when transmitting RAW or LONG RAW data. In contrast, Oracle Net and Import/Export automatically convert CHAR, VARCHAR2, and LONG data from the database character set to the user session character set (which you can set with the NLS_LANGUAGE parameter of the ALTER SESSION statement), if the two character sets are different.
When Oracle automatically converts RAW or LONG RAW data to and from CHAR data, the binary data is represented in hexadecimal form, with one hexadecimal character representing every four bits of RAW data. For example, one byte of RAW data with bits 11001011 is displayed and entered as CB.
-k