sitecore7 - Sitecore 7.5 logs TypeLoadExceptionHolder cannot be converted to type Sitecore.Analytics.Model.Framework.IFacet -

i having following error in sitecore 7.5 logs. idea why getting error?.

9660 13:14:42 info httpmodule being initialized heartbeat 13:15:26 error exception in alarm clock event subscriber. exception: system.argumentexception message: object of type 'system.runtime.serialization.typeloadexceptionholder' cannot converted type 'sitecore.analytics.model.framework.ifacet'. source: mscorlib @ system.runtimetype.trychangetype(object value, binder binder, cultureinfo culture, boolean needsspecialcast) @ system.reflection.rtfieldinfo.unsafesetvalue(object obj, object value, bindingflags invokeattr, binder binder, cultureinfo culture) @ system.runtime.serialization.objectmanager.dovaluetypefixup(fieldinfo membertofix, objectholder holder, object value) @ system.runtime.serialization.objectmanager.completeobject(objectholder holder, boolean bobjectfullycomplete) @ system.runtime.serialization.objectmanager.donewlyregisteredobjectfixups(objectholder holder) @ system.runtime.serialization.objectmanager.registerobject(object obj, int64 objectid, serializationinfo info, int64 idofcontainingobj, memberinfo member, int32[] arrayindex) @ system.runtime.serialization.formatters.binary.objectreader.registerobject(object obj, parserecord pr, parserecord objectpr, boolean bisstring) @ system.runtime.serialization.formatters.binary.objectreader.parseobjectend(parserecord pr) @ system.runtime.serialization.formatters.binary.__binaryparser.run() @ system.runtime.serialization.formatters.binary.objectreader.deserialize(headerhandler handler, __binaryparser serparser, boolean fcheck, boolean iscrossappdomain, imethodcallmessage methodcallmessage) @ system.runtime.serialization.formatters.binary.binaryformatter.deserialize(stream serializationstream, headerhandler handler, boolean fcheck, boolean iscrossappdomain, imethodcallmessage methodcallmessage) @ system.runtime.serialization.formatters.binary.binaryformatter.deserialize(stream serializationstream, headerhandler handler, boolean fcheck, imethodcallmessage methodcallmessage) @ sitecore.analytics.data.dataaccess.submitqueue.filesubmitqueue.dequeue() @ sitecore.analytics.submitqueueservice.wakeup() @ sitecore.services.alarmclock.heartbeat_beat(object sender, eventargs e)

it looks there somethings submit queue.

take @ "submit queue" folder in sitecore "datafolder" directory. remove wrong files , check file permissions.