Execution of the managed stored procedure Format failed with the following error: Microsoft::AnalysisServices::AdomdServer::AdomdException.

Below is my mdx query written in microsoft analysis services:

WITH
MEMBER [Measures].[DateMax] AS
    STRTOMEMBER("[INT TIME].[INT TIME].&["+Format([Measures].[2013-08-29T00:00:00], 'yyyy-MM-ddTHH:mm:ss')+"]")

MEMBER [Measures].[DateBefore3Months] AS
    Format(DateAdd('m', -2, [Measures].[DateMax]), 'yyy-MM-01T00:00:00')

SELECT
non empty { [Measures].[DURATION],
    [Measures].[SELL VALUE],
    [Measures].[BUY VALUE],      
    [Measures].[PERCENTAGE]}  on columns,
non empty (
    {STRTOMEMBER("[INT TIME].[INT TIME].&["+[Measures].[DateBefore3Months]+"]"):STRTOMEMBER("[INT TIME].[INT TIME].&["+[Measures].[DateMax]+"]")},
    [CUSTOMER PROFILES].[CUSTOMER].[CUSTOMER]
    ) on rows
FROM [Cube1]

The error i am getting is :

Execution of the managed stored procedure Format failed with the following error: Microsoft::AnalysisServices::AdomdServer::AdomdException.
Query (3, 72) The '[2013-08-29T00:00:00]' member was not found in the cube when the string, [Measures].[2013-08-29T00:00:00], was parsed.

Please suggest where is the problem in this query and how can I resolve it.