Warning: trim() expects parameter 1 to be string

Just downloaded this for our club website as a way of making a pdf version of our website stories (for those who havent joined us in the computer age yet)

I am getting this error (obviously removing my site details)

Warning: trim() expects parameter 1 to be string, array given in xxxxxxxxxxx/wp-content/plugins/make-pdf-newspaper/libraries/phphooks/phphooks.class.php on line 185

then it throws

Warning: fopen(/home/johnjack/public_html/blacksheep/wp-content/pdf/newspaper–cat-3.pdf) [function.fopen]: failed to open stream: No such file or directory in xxxxxxxxxx/wp-content/plugins/make-pdf-newspaper/libraries/tcpdf/tcpdf.php on line 7239

which I think is a symptom of the first error

Can anyone help?
It does this if I dont make any changes to the default information.
Looks as though a field is being submitted in the wrong datatype.

Using Arras Theme on Lates version of wordpress, latest version of plugin

Please help as really like the look of this plugin, it seems to do so much more than any of the others out there

Thanks

JohnJack

http://wordpress.org/extend/plugins/make-pdf-newspaper/