No, it is absolutely sound by the scriptures for live humans to pray for one another, and by extension to ask for it. When my friend asks me to pray for him, not only does it benefit him for the fact of my prayer, but it also benefits me in the making of it. I see this as completely different from praying to deceased saints who may or may not actually be in Heaven. What scripture is used to defend the propriety of praying to the physically deceased for intercession with God?
I think the crux of the difference is that some of you view the Saints as "a bunch of dead guys." Catholics view them as very much alive and available to them.
Well in a sense, they ARE a bunch of dead guys. :) We believe that upon physical death the saved among them go directly to Heaven, where they are very "alive". This includes any or all of who you would call the Saints. This is scriptural. However, I am not certain of the scripture that says that these "spirits" are actually available to us.
I have been told by other Catholics that it is permissible to pray to such others as deceased relatives for intercession. Is that your understanding as well? If it is, and if you would agree that it would be a waste of time to pray to a "spirit" in purgatory or hell, then how does a Catholic make such a prayer with any confidence since one cannot know where the "spirit" of a lost relative is?