mongodb socialdev test.js
raises:

Mon Sep 26 11:48:04 uncaught exception: map reduce failed:{
"assertion" : "value has to be set",
"assertionCode" : 10210,
"errmsg" : "db assertion failure",
"ok" : 0
}

mongodb anothercollection test.js
OK

what is happening to my collection, it has very important data.