In certain situations novaPDF won't show any PDF save dialog or error message when you are trying to create a PDF file from a document. If novaPDF is installed correctly then the issue can be due to the dimensions of the page being printed. In Windows 7/8/8.1 there is a limitation for the document print size and if that's exceeded then you won't be able to print (i.e. to a regular printer or a virtual one such as novaPDF) unless you do a registry change.
For example, trying to create a PDF file from a one page document at 600x600 DPI (with a printable area of 40" x 300") will fail. The same page will be printed fine however when being printed at 300x300 DPI. The problem occurs if the (Paper Width in inches * dpi) * (Paper Length in inches * dpi) results in a number larger than 4GB (0xFFFFFFFF). This is a limitation imposed by Windows, it's not because of novaPDF.
In order to allow printing such large documents to PDF you can add a registry DWORD and set its value to 2.
Path where to add the registry DWORD:
Name of the registry key: