I just installed CDdisplay to view these type of files, but when you double-click the files I get an error message:
"An error occurred reading 'xxx.cbz' file: the file appears to be invalid or damaged".
However, the file opens correctly with Windows Explorer.
¿Any ideas?
Sorry for my english, my native language is spanish.
Please try turning off CBZ under Preferences / Zip & Other Archives / Archive and VFS Plugins. That will stop Opus trying to open the file itself and allow the other program to open it instead.
If that fixes it, could you send me one of the files that causes the error, so that I can take a look at why it isn't opening in Opus? You can email it to leo@gpsoft.com.au or send me a private message with it as an attachment. (If you send a private message, please zip the cbz file, so that the forum allows you to upload it.)
PS: Your English is fine, don't worry. 
"Please try turning off CBZ under Preferences / Zip & Other Archives / Archive and VFS Plugins."
That worked.
I'm sending an e-mail with the file.
Thank you.
Thanks for the file!
The reason it did not open in Opus is that its extension is wrong.
It is a .cbr (RAR) file not a .cbz (ZIP) file.
If you rename it to .cbr then it will work in Opus, and you can turn CBZ back on within Preferences (which will give you nice thumbnails for CBZ files in Opus).