CaRP: Caching RSS Parser - Documentation
CaRP Interactive FAQ
The feed either contains characters that cannot be displayed in the character encoding used by your webpage, or CaRP isn't outputting the feed in the correct encoding for your webpage.
By default, CaRP converts all feeds to a character encoding called ISO-8859-1. This is the encoding used internally by the PHP programming language. If the feed contains such things as "smart quotes", certain accented characters, multi-byte characters (like Chinese), etc., they will be converted to question marks because ISO-8859-1 does not support these characters.
If rather than question marks, you're seeing "garbage characters", then most likely, you've told CaRP to convert the feed to the encoding UTF-8, but your webpage is not encoded in UTF-8.
Click for solutions to these problems.