There hasn’t been a lot of news on this. I’m thinking there must not be a whole lot to the allegations overall, though, or we’d be hearing a whole lot more about it.
I did notice this in an AP/MSNBC.com article, though:
Word of the review came Monday as Sunni Arab leaders repeated accusations of fraud after initial reports from the provinces suggested the constitution had passed. Among the Sunni allegations are that police took ballot boxes from heavily “no” districts, and that some “yes” areas had more votes than registered voters. [emphasis mine]
The losing party/group is claiming fraud.
And critics thought the Iraqi people wouldn’t understand how democracy worked.
For what it’s worth, we can probably dismiss the “more votes than registered voters” accusation, if only because every time Republicans make it in America we’re treated to dozens of reasons why the supposed violation isn’t really anything to worry about. (I’m sure it goes the other way some times, as well. I just don’t recall hearing anything about it recently.)