Error-2147352567 The specified printer is invalid

[kivi]

           I have designed a PrinterControl.vi use the funcitions at the Report Generation subpalette. And I have installed two virtual printers in my computer.The name of one is VirtualPrinter0,the other is VirtualPrinter1.While I use Print Report.vi ,I want to use a case struction to wire a printer name in order to realise printer selection function.When I select VirtualPrinter1,the vi can work properly.However while I select  VirtualPrinter0,I get Invalid printer name error( Error-2147352567).
        Strange still ,when I use the two printers separately,the vi can also work well.I am working with Labview 7.1.I don't know What the problem is.Hope to get help,thanks in advance for your help.
                  kivi

[Liming]

Hi kivi,

If the two virtual printers could both be used in the same VI, I think it should have no problem to add a case structure. 

It's a bizarre problem. Could you attach your VI?

[kivi]

hi,LiMing

 First of all,   I  really appreciate your help! The  vi and the outcome  are  attached in the inclosure .Thanks again for your help!

[kivi]

hi,LiMing

 First of all,   I  really appreciate your help! The  vi  is attached in the inclosure .Thanks again for your help