What version of LabVIEW are you using? If you are using version 5.1, make sure you have the 5.1.1 update installed. If you are using version 6.0, make sure you have the 6.0.2 update installed. Both of these updates are available from the NI website.
Also, one possible solution to the "bad type" error is to search your diagram for "coercion dots", where you have wired a source and a sink of different types. LabVIEW will perform the proper conversion to get the data into the same type, but I have seen extremely rare cases in the past where the conversion had to be performed explicitly in the diagram in order to avoid the error. You can find the datatype conversion functions in the Numeric >> Conversion subpalette.
Good luck with your applicati
on, and have a nice day.