First of all, make sure that you have the latest versions of the PadMu Apps installed , you can check it from the eINK store.

Update them and try again :

If you get a "-3" error message while opening a file is because either :

1. you tried to open it directly from the system folders of the tablet using the file manager interface
2. you imported the file into the PadMu Library , but at least once you tried to open it directly from the system folders of the tablet using the file manager interface

Solution :

1. delete the file from the PadMu Library (if you have it in there)
2. delete the file from the system folder where it is
3. copy again from the PC /Mac into the the "PadMu Default Import" folder
4. from the PadMu Library , click on "Add file" , choose "Default Directory" and import the file.