Date Conversion Error

hi guys,

i am passing date value from a textbox in c# and asp.net.
i am calling an sql procedure .
The result is binding to a datagrid.
my sql procedure is like this


create procedure searchComplaintdetails
(
@FirstName nvarchar(50),
@DueDate DateTime

)
as
DECLARE @SQL varchar(5000)
SET @SQL = 'select Customers.CustomerFirstName as Name,ComplaintLog.LogDate,ComplaintLog.LogID,
ComplaintLog.ComplaintStatus,ComplaintLog.DueDate,ComplaintCategories.CategoryName from ComplaintLog
Join ComplaintCategories on ComplaintLog.CategoryID=ComplaintCategories.CategoryID
join Customers on ComplaintLog.CustomerID=Customers.CustomerID
where ComplaintLog.IsActive=1'


IF Datalength(@FirstName)>0
SET @SQL = @SQL + ' AND Customers.CustomerFirstName LIKE ''' + @FirstName + '%'''

IF Datalength(@DueDate)>0
SET @SQL = @SQL + ' AND Convert(DateTime(10),ComplaintLog.DueDate,101) = '+@DueDate + ' '


EXEC (@SQL)
GO

my error is Syntax error converting datetime from character string.

if i pass nothing in test boxit will show another error

SqlDateTime overflow. Must be between 1/1/1753 12:00:00 AM and 12/31/9999 11:59:59 PM.