Here is the corrected statement:
SET @StartDate = convert(VARCHAR(10), getdate(), 101)
+ ' ' + (CAST(DATEPART(hh, (SELECT [Value] FROM tbltime WHERE NAME='TIME')) AS VARCHAR)
+ ':' + CAST(DATEPART(mi, (SELECT [Value] FROM tbltime WHERE NAME='TIME')) AS VARCHAR)
+ ':' + CAST(DATEPART(ss, (SELECT [Value] FROM tbltime WHERE NAME='TIME')) AS VARCHAR)
-- unmark the line below if you want to display the miliseconds in the result
--+ '.' + CAST(DATEPART(ms, (SELECT [Value] FROM tbltime WHERE NAME='TIME')) AS VARCHAR)
)