VBScript in Reports Expression Editor, filtering out certain values

I have a report that need null values replaced with N/A. It works for x amount of rows until the null value is hit then the rest of the data needing to be displayed just goes away.

Here is my expression

=iif(Fields!PastBaseline.Value is nothing, "N/A开发者_开发百科", Round(Fields!PastBaseline.Value))

Anyone know what I am doing wrong?

I have used similar things many time and it works fine. Try it like this:

=iif( IsNothing( Fields!PastBaseline.Value ), "N/A", Round(Fields!PastBaseline.Value))

If this does not work can you see if there are any errors or warnings.