I found the problem, there are 2 ways you can fix it.
Assuming you are using the latest version of Fund Raiser Pro, you can download it again and replace the file PayPalCheckout.aspx which I just edited.
or you can edit your current copy of that file with any text editor like notepad. Just look for WebInvoiceResources which exists in one spot, and change it to FundRaiserResources
Thanks,
Joe