I've followed ET documentation regarding pulling data from RSS feed to email that can be found here:

http://help.exacttarget.com/en/documentation/exacttarget/content/ampscript/how_to_include_an_rss_feed_in_an_email_message_using_ampscript/

I've created simple code:

    %%[
    SET @xmlTemp = ContentAreaByName("my contents\XML\XMLtest")
    SET @xml = Replace(@xmlTemp, "content:encoded", "contentencoded")
    SET @titles = BuildRowsetFromXML(@xml,"//item/title",1)
    ]%%
    
    %%=Field(Row(@titles, 1), 'Value')=%%
It works fine when it's implemented in landing page but generates error when it's used in email. I tried to wrap output into TreatAsContent() but still nothing