[X4U] what is "OOPlistDocumentType" preference file ?

[Andrew J. Yon III]

A friend of mine and I are using OSX 10.4.8 and we each are on ichat  
(the same versions). I can send him files thru ichat but he can not  
send files to me. When He tries, I get message "waiting on him to  
start " and his gives message " waiting on me to accept". However, he  
can send me files using Skype. I decided he must have a bad ichat  
preference file . In checking his user prefs, we found that my prefs  
listed under kind end with .plist , but his are listed under kind as   
OOPlistDocumentType. He is using a G5 and I am using a MDDP G4. I can  
not find any reference to this type file on Apple's site. I have  
never seen it before , so I am not sure if it is a valid type file.  
Can anyone give me any ideas on what could be wrong ? Also is  
OOPlistDocumentType a valid type of plist ?

Andy3