"book-toc-** in menu_tree_build" Error appears when creating a new book in Drupal 7.2

When one tries to create their first "book" in Drupal 7.2, things go smoothly enough. But difficulties soon arise when one tries to create the second or any subsequent books, for an error message appears during the moments one is actually creating these additional books. This issue and a possible solution for it is discussed here: http://drupal.org/node/990260

The error message displayed is:

end() [function.end]: Passed variable is not an array or object in file_managed_file_validate() (line 536 of C:\Users\Mark\Zip Based Installers\xampp\htdocs\thelist\modules\file\file.module)

This is apparently due to a bug in the core's file module. After applying the patch as described above to the file module, the said error message disappears and additional books can be added with no errors.

In my particular install, in addition to the "Book" content type, an additional content type called "Portfolios" was created and in the book module configuration settings, "Portfolios" was checked as an additional content type that "inherits" the book modules navigation features. Multiple books and "portfolios" were then created and all this went along perfectly.

In order to improve the navigation of these various "books", the "menu block" module was chosen and used in the sidebar to aid in the navigation of said books.

The problem was that once the menu block was activated and it was configured by going to structure/blocks/ add menu block, an error message suddenly appears on each page of each book! The error message is this:

book-toc-34 in menu_tree_build() (line 262 of C:\Users\Mark\Zip Based Installers\xampp\htdocs\thelist\sites\all\modules\menu_block\menu_block.module)

Page reloads do not help remove this message. The error message just stays there whenever any book page is viewed. If however the menu block module is disabled and then re-enabled, then the error messages disappear and everything works fabulously. Until the next book is added that is where disabling and re-enabling the module removes said appearing error messages.

Any help or guidance much appreciated!

Regards
Mark