deserialisation errors

Hi, 
 Using the latest tarball, on a clean postgresql db (8.4 and 9.1, if it makes a
difference), I'm getting a lot of this sort of thing: 
(5-6 a page, often more). 
 
Notice: "unserialize(): Error at offset 0 of 152 bytes" 

Is this a known issue? I don't see anything in my apache logs, or in the
firefox console.

David
ps I'm connecting to the DB using method sql. Should I try swiching to
adodb?


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