Sorry for being out so long, guys, but dhavalbsolanki has actually raised an interesting point; if the domain or some other config setting is inconsistent, there may be a problem with the server setting or reading it's cookies, but that's equally a browser issue as a server issue, since it's the browser's responsibility to send the requested cookie back.
Honestly, very strange; thejojk - did your error get cleaned up as a result of this thread, or is it still happening?