I updated my PA frameworks copy of IrfanView four days ago, and soon found I couldn't save any updates to my preferences. IrfanView warned me of this as soon as I entered the Options dialog, saying
Your INI file 'D:\Development\Portable Apps\IrfanView\Releases\IrfanViewPortable\Data\IrfanView\i_view.ini' is read-only.
I don't even have a D drive. I think the PA packager has inadvertently left a trace of their system in the released code.
I fixed this by finding the file which specified that file path. It was in a plain text .INI fle at
(my install location)\PortableApps\PortableApps\IrfanViewPortable\App\IrfanView\i_view32.ini
where one line contained:
Once that was changed so that it pointed to
(my install location)\PortableApps\PortableApps\IrfanViewPortable\Data\IrfanView
everything worked again.