From version 3.0
"replaced non-free UnRAR with a free RAR extraction library. If some CBR files fail to open for you, download unrar.dll from http://www.rarlab.com/rar_add.htm and place it alongside SumatraPDF.exe"
The portable apps doesn't have the option to install unrar.dll from rarlabs.com.
Any chance?
Sorry for my english
Thanks