Need help transforming a string to a date using SSIS expression

Hi,

    I've been banging my head against the wall with this.  My flat file import has a dozen dates as strings in the format "YYYYMMDD", i.e.,  "20120517".  When I run the Data Flow with this Derived column (which is added) using expression :

(DT_DBDATE)(SUBSTRING(LRDDTES_01,5,2) + "-" + SUBSTRING(LRDDTES_01,7,2) + "-" + SUBSTRING(LRDDTES_01,1,4))

I get the error message(s) in the execution results at the end of this post. Not sure what else I can do.  There are no nulls or bad strings in any of the records. I also created a string column using (SUBSTRING(LRDDTES_01,5,2) + "-" + SUBSTRING(LRDDTES_01,7,2) + "-" + SUBSTRING(LRDDTES_01,1,4)) and the column yields "05-17-2012".

Scratching my head............................

BTW: I'm using Visual Studio 2012 Pro and SQL Server 2012 Standard

Error messages below:

[FES-DERIVED-CUSTOMERINFO [2]] Error: An error occurred while attempting to perform a type cast.

[FES-DERIVED-CUSTOMERINFO [2]] Error: SSIS Error Code DTS_E_INDUCEDTRANSFORMFAILUREONERROR.  The "FES-DERIVED-CUSTOMERINFO" failed because error code 0xC0049064 occurred, and the error row disposition on "FES-DERIVED-CUSTOMERINFO.Outputs[Derived Column Output].Columns[T_DATE_TEST_DB]" specifies failure on error. An error occurred on the specified object of the specified component.  There may be error messages posted before this with more information about the failure.

[SSIS.Pipeline] Error: SSIS Error Code DTS_E_PROCESSINPUTFAILED.  The ProcessInput method on component "FES-DERIVED-CUSTOMERINFO" (2) failed with error code 0xC0209029 while processing input "Derived Column Input" (3). The identified component returned an error from the ProcessInput method. The error is specific to the component, but the error is fatal and will cause the Data Flow task to stop running.  There may be error messages posted before this with more information about the failure.

[FES-SOURCE-CUSTOMERINFO [274]] Error: The attempt to add a row to the Data Flow task buffer failed with error code 0xC0047020.

[SSIS.Pipeline] Error: SSIS Error Code DTS_E_PRIMEOUTPUTFAILED.  The PrimeOutput method on FES-SOURCE-CUSTOMERINFO returned error code 0xC02020C4.  The component returned a failure code when the pipeline engine called PrimeOutput(). The meaning of the failure code is defined by the component, but the error is fatal and the pipeline stopped executing.  There may be error messages posted before this with more information about the failure.