gem encoding issue

Hi all, I’m trying to install mysql on windows 7:

I input this command:

gem install mysql – --no-rdoc --with.mysql-lib=X:

where X: = C:\MySql\lib

and throws the following exception

ERROR: While executing gem … (Encoding::UndefinedConversionError) U+2019 from UTF-8 to CP850.

I’m using windows 7 professional N, Ruby 1.9.2-p0 and mysql 5.5

I looked up in some forums and I read that I’ve to change my encoding, but, How do I to do that?

Please, I’ll really appreciate it.