General run error. tdc.InitConnectionEx sQCUrl

Hi,

I am getting General run error (tdc.InitConnectionEx sQCUrl) while connecting to QC using the below code, this code was worked many times and I automated few scenarios. Suddenly the same code is giving trouble, can some one help me what is the root cause of the issue.

Note: No version changes, no code changes, suddenly get the error. Current Version is QC 11 and QTP 11

sQCUrl = "http://qcport/qcbin"
sUsername = Parameter("UserID")
sPassword =  Parameter("Password")
sQCDomain = "qcdomain"
sQCProject = "qcproject"

Set tdc = CreateObject("TDApiOle80.TDConnection")   'tdc Object set successfully, and i can see sub objects availability

tdc.InitConnectionEx sQCUrl

'at above line I am getting General run error

tdc.Login sUsername, sPassword          'QC Authentication

If (tdc.LoggedIn <> True) Then
 MsgBox "User " & sUsername & " Authentication to ALM is Fail"  
End If

tdc.Connect sQCDomain, sQCProject       'QC Project Login

If (tdc.Connected <> True) Then
 MsgBox "ALM Project Failed to Connect to " & sQCProject
End If

If tdc.Connected Then : tdc.Disconnect
If tdc.LoggedIn Then : tdc.Logout