Failed to create KVP sessions string. Error Code 0x8007007A

I have two RDS servers running Server 2012, and since a couple of days users are reporting they get disconnected often. In the eventlogs, I found a couple of events where a user was disconnected without further information. I also found a lot of "Failed to create KVP sessions string" events. I couldn't find any relevant information about this event, but it appears the most at moments when users are being disconnected from the RDS server.

This is the event:

Log Name:      Microsoft-Windows-TerminalServices-RemoteConnectionManager/Operational
Source:        Microsoft-Windows-TerminalServices-RemoteConnectionManager
Date:          3/12/2013 10:01:26 AM
Event ID:      1152
Task Category: None
Level:         Error
Keywords:     
User:          SYSTEM
Computer:      TS02.contoso.com
Description:
Failed to create KVP sessions string. Error Code 0x8007007A
Event Xml:
<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
  <System>
    <Provider Name="Microsoft-Windows-TerminalServices-RemoteConnectionManager" Guid="{C76BAA63-AE81-421C-B425-340B4B24157F}" />
    <EventID>1152</EventID>
    <Version>0</Version>
    <Level>2</Level>
    <Task>0</Task>
    <Opcode>0</Opcode>
    <Keywords>0x1000000000000000</Keywords>
    <TimeCreated SystemTime="2013-03-12T09:01:26.771581100Z" />
    <EventRecordID>11344</EventRecordID>
    <Correlation />
    <Execution ProcessID="836" ThreadID="840" />
    <Channel>Microsoft-Windows-TerminalServices-RemoteConnectionManager/Operational</Channel>
    <Computer>TS02.contoso.com</Computer>
    <Security UserID="S-1-5-18" />
  </System>
  <UserData>
    <EventXML xmlns="Event_NS">
      <Param1>2147942522</Param1>
    </EventXML>
  </UserData>
</Event>

Does someone have any idea what might cause this error? Thanks!