And do you have reason to believe that this data would show positive or negative autocorrelation? i.e. do you need to do a one or two sided test? Often a two sided DW test is simply carried out as two one sided tests and the $\alpha$ (type I error) for the two sided is simply doubled. So for example for the test:
$H_o: \rho = 0$
$H_a: \rho \neq 0$
Decision rule is as follows:
$If DW(2.207) > dU \rightarrow Fail\ to\ Reject\ H_o$
$If DW(2.207) < dL \rightarrow Reject\ H_o$
$if dL < DW < dU \rightarrow Test\ is\ inconclusive$
that would test for $\rho > 0$. For $\rho < 0$ the test is 4-DW (2.207), everything else is similar (e.g. if $4-DW < dL \rightarrow conclude\ \rho < 0$) But like I said above, since you've carried these two tests out seperately, if you've tested them both at the $\alpha = 0.05$ level, then you don't have the two sided test at that level. You've got the test at the $2\alpha$ level. So change your $\alpha$ level accordingly to get the desired result.