VMWARE ESXi Tools ERROR "[ warning] [vmusr:vmusr] Error in the RPC receive loop: RpcIn: Unable to send"

After installing ESXI tools you may receive this error:

[ warning] [vmusr:vmusr] Error in the RPC receive loop: RpcIn: Unable to send.

It seems an upgrade problem and just recreate/reconfigure tools.conf:

"You can create it like this:

[logging]
log = true
# Enable tools service logging to vmware.log
vmsvc.level = debug
vmsvc.handler = vmx
# Enable new "vmusr" service logging to vmware.log
vmusr.level = error
vmusr.handler = vmx
# Enable "Volume Shadow Copy" service logging to vmware.log
vmvss.level = debug
vmvss.handler = vmx

Save it as tools.conf in the appropriate folder for the guest OS.
Windows XP and Windows Server 2000/2003
C:\Documents and Settings\All Users\Application Data\VMware\VMware Tools\tools.conf
Windows Vista, Windows 7, and Windows Server 2008
C:\ProgramData\VMware\VMware Tools\tools.conf"

More info: http://adf.ly/EoNGe
Source: VMWare Knowledge Base