Recently, I was trying to convert some manga .cbz and PDFRead failed (miserably). The .cbz was just a .zip file with .jpg images, but it was done so as to break the simplistic .cbz module (I wrote) within PDFRead.
Originally the .cbr/.cbz files I tried when writing the code worked for me. 
The sample .cbz I used downloaded as a .zip and when renamed to .cbz would not convert. The reason being that a directory was used within to hold all the images and to make matters worse, another directory was also present with links to .jpg images (MACOSX remmanents!).
I found a simple workaround to allow PDFRead to convert the .cbz, namely:
1. unzip the .zip (.cbz) and search for the directory with the main pictures.
2. start PDFRead and from the Input box, browse to that main pictures directory above and double-click any image therein.
3. select the 'imgdir' In Format and insert the title, author, and category.
4. select your preferred profile and layout mode and click the Convert button.
5. your resulting file will be in that main pictures directory.
Below I provide some sample conversations for the EBW1150 done using this workaround method. Please use this method
until PDFRead can be improved to better handle the ever increasing use and differing electronic storage of manga/comic books.
Thanks to Nekokami for pointing me in this direction...
p.s. sorry but I forgot to change the ebook author description for the landscape versions; my bad!