Arithmetic overflow error converting expression to data type datetime in SQL Server 2008

I am executing below SQL Script which is throwing error Arithmetic overflow error converting expression to data type datetime

I have searched for this error in SO and google but I'm not able to figure out the solution.

Below is mine Longggggggggg SQL Query

DECLARE @TimeByDay DATETIME 
DECLARE @TimeByDay2 DATETIME

SET @TimeByDay = '1/1/2012'
SET @TimeByDay2 = '12/31/2014'


SELECT  p1.ProjectName ,
        p1.EnterpriseProjectTypeName ,
        p1.[Legacy System ID] ,
        p1.ProjectDescription ,
        p1.ProjectOwnerName ,
        p1.[Gate Approvers] ,
        p1.[Team Members] ,
        p1.[Project Sponsor] ,
        p1.[Idea Project Type] ,
        p1.[Compliance Project] ,
        p1.[Product Category] ,
        p1.[Relevant Functional Area] ,
        p1.Initiative ,
        p1.[OPEX Transformation] ,
        p1.[Commodity Type] ,
        p1.[LSS Training Project] ,
        p1.[Project Status Comments] ,
        p1.[Project Status] ,
        p1.Phase ,
        p1.[Innovation Matrix Class] ,
        p1.[Legacy Project Manager] ,
        p1.[AOP Line Number] ,
        p1.[AOP Project Name] ,
        p1.[Approval Level] ,
        p1.Assumptions ,
        p1.[Belt Name] ,
        p1.[Benefits Impact] ,
        p1.[Bus Impact or Bus Y] ,
        p1.[Business Sponsor] ,
        p1.[Code Name] ,
        p1.[Complexity Risk Level] ,
        p1.[Complexity Risk Score] ,
        p1.[Critical to Quality] ,
        p1.Deliverables ,
        p1.[Development Risk] ,
        p1.[Estimated Duration] ,
        p1.[Financial Uncertainty] ,
        p1.[Financial Rep] ,
        p1.[External Dependencies] ,
        p1.[Financial Risk Level] ,
        p1.[Financial Risk Score] ,
        p1.[Idea Functional Area] ,
        p1.[Idea Beneftting Location] ,
        p1.[Idea Reviewer Comments] ,
        p1.[Idea Comments] ,
        p1.[Idea Sector] ,
        p1.[Idea Submitters Email] ,
        p1.[Idea Submission Date] ,
        p1.[Idea Submitter Phone] ,
        p1.[Idea Reviewer Name] ,
        p1.[Idea Description_] ,
        p1.[Idea Est Revenue Benefit] ,
        p1.[Idea Name] ,
        p1.[Idea Product Category] ,
        p1.[Idea Est Savings Benefit] ,
        p1.[Idea Number] ,
        p1.[Idea Review Date] ,
        p1.[Idea Est Balance Sheet Benefit] ,
        p1.[Idea Est Investment] ,
        p1.[Idea Submitter Email] ,
        p1.[IR Project Type] ,
        p1.[Idea Sources] ,
        p1.[Idea Submitter] ,
        p1.[Implementation Risk] ,
        p1.[Technology Capabilities Risk] ,
        p1.[Market Uncertainty] ,
        p1.[Legal Regulatory Risk] ,
        p1.[Investment Risk] ,
        p1.Mentor ,
        p1.[Out of Scope] ,
        p1.[Project Scope] ,
        p1.[Project Start Date] ,
        p1.[Project Finish Date] ,
        p1.[Mandated by whom?] ,
        p1.[Reason for Action] ,
        p1.[Project Champion] ,
        p1.[Process Owner] ,
        p1.[Target State (Box 3 of A3)] ,
        p1.[Problem Statement] ,
        p1.[Project Interaction] ,
        p1.[Strategic Goal/Business Case] ,
        p1.[Sending Leader(s)] ,
        p1.[Receiving Leader(s)] ,
        p1.[Process Definition] ,
        p1.[Things That Can Be Improved] ,
        p1.[Idea Estimated Duration] ,
        p1.[ST IT Cost Center] ,
        p1.[Top Project] ,
        p1.[Reason For Action (Box 1 of A3)] ,
        p1.[Initial State] ,
        p1.[Impact of not meeting mandate] ,
        p1.[Primary Proponent Department] ,
        p1.[Project Financial Benefit Status] ,
        p1.[Project Resource Status] ,
        p1.[Project Schedule Status] ,
        p1.[Project Investment Status] ,
        p1.[Project Success Factors] ,
        p1.[Support Required] ,
        p1.[Project Milestones] ,
        p1.[Project Constraints] ,
        p1.[Other Funding Source] ,
        p1.[Project Cost Center] ,
        p1.[Initial State (Box 2 of A3)] ,
        p1.CostCenterName ,
        p1.CostCategoryName ,
        YEAR(p1.TimeByDay) AS Year ,
        MONTH(p1.TimeByDay) AS Month ,
        p1.Actuals ,
        p1.Budget ,
        p1.Forecast ,
        p1.PhaseName ,
        p1.ProjectUID ,
        CONVERT(VARCHAR(20), p1.ProjectCreatedDate, 101) AS ProjectCreatedDate ,
        CONVERT(VARCHAR(20), p1.ProjectModifiedDate, 101) AS ProjectModifiedDate
FROM    [IR.ST.EPM Custom Flds and Financial Data] p1
--WHERE   p1.TimeByDay >= CAST(@TimeByDay AS DATETIME)
--        AND p1.TimeByDay <= CAST(@TimeByDay2 AS DATETIME)
WHERE p1.timebyday >= @TimeByDay
        AND p1.timebyday <=@TimeByDay2
        AND p1.StageEntryDate IS NOT NULL
        AND p1.StageCompletionDate IS NOT NULL

I'm not sure what needs to be change here.

Sorry for duplicate!