The following runs without error on my system. I had to correct some errors in the code provided.

You will want to run the following in a sandbox database first as I do create and drop the parameter_value table.

--Example Data values (key_value):

create table dbo.parameter_value (

pvid int identity(1,1),

datatype char(1),

key_value varchar(64)

);

insert into dbo.parameter_value(datatype, key_value)

values

('D','2013-10-29 22:59:00Z'),

('D','2013-04-25 23:59:00Z'),

('D','2013-03-06 22:59:00Z'),

('D','2013-03-06 22:59:00Z'),

('D','2013-03-06 22:59:00Z'),

('D','2013-03-29 22:59:00Z'),

('D','2013-03-06 22:59:00Z'),

('D','2013-04-27 23:59:00Z'),

('D','2013-03-06 22:59:00Z'),

('D','2013-04-03 23:59:00Z');

go

SELECT TOP 10 key_value

,convert(datetime2,PV.key_value) as DT2

,convert(datetime,CONVERT(DATETIME2, PV.key_value)) AS DT

FROM parameter_value PV

WHERE PV.datatype = 'D';

go

SELECT TOP 10 key_value

,convert(datetime2,PV.key_value) as DT2

,convert(datetime,CONVERT(DATETIME2, PV.key_value)) AS DT

FROM parameter_value PV

WHERE PV.datatype = 'D'

and convert(datetime,CONVERT(DATETIME2, PV.key_value)) BETWEEN GETDATE() and DATEADD(d, 10, GETDATE())

go

drop table dbo.parameter_value;

go