Parapundit has been running a series of pieces regarding the possibility that the United States was spoon-fed bad Human Intellegence (HUMINT) reports regarding WMD in Iraq by Chalabi vis Iran. I have no particualr insight into the facts behind these specific reports but Parapundit seems to lack a bit of understanding regarding the reliability of of HUMINT when they say things like this :
"They need the level of talent (particularly in science and technology but also in cultural knowledge and economics training) that would allow them to see through deceptions which they currently are easily fooled by."
The fact of the matter is that very rarely will an agency receive a report regarding WMD from someone who is technobabbling them. They are far more likely to receive very vague statements and anecdotal tales from lower-level folks who wouldn't have the technical chops to even attempt technobabble. All they have to do is come up with anything semi-plausible like, "My boss said they were getting in a Uranium shipment!" If you generate a large enough volume of such reports the isolated technicalreport that seems to have suspect details in it is completely lost in the deluge.
Once you start to offer money for information regarding certain well known subjects you can count on receiving plenty of juicy-sounding and unconfirmable reports every day. Even if the respondents have no actual knowledge of actual intelligence worthy activities. This is an easy source of untraceable income to many folks in foreign governments and they will not be shy about lying to get them a piece of the action. There is a reason that HUMINT reports are also referred to as "creative writing assignments".
You will never cease to be fooled if you base decisions on paid informants. They have no loyalty to you and they already know what you want to hear. Don't be surprised when you hear it then.