You've already found the pipc.log file, which is one source of information for troubleshooting.
Another one would be the PI OPC DA/HDA Server debug log file, to be setup according to these instructions from the PI OPC DA/HDA Server documentation:
If debugging is turned on, debug messages are written to the specified debug log according to the value of the debug flags.
Debugging is controlled via the registry. The server creates a set of registry keys upon installation, which can be viewed via the regedit program supplied with Windows (at the start button, select Run... and type regedit into the box, then select OK) or through the use of the PI OPC DA/HDA Server configuration tool (OPCServerConfigTool) which modifies the registry keys directly. The registry keys that control debugging are stored under HKEY_LOCAL_MACHINE/SOFTWARE/PISystem/PI_OSIOPC/Data and HKEY_LOCAL_MACHINE/SOFTWARE/PISystem/PI_OSIHDA/Data and are called LogFile, DebugArea, and DebugLevel as displayed below.
Regardless of insights other vCampus members might have to share with you on this topic, I kindly invite you to contact our regular Technical Support to get assistance on this issue, as this is not really related to programming issues, but configuration. Here in vCampus we try to stay focused on programming and systems integration (from an architectural and design perspective) involving PI.
For troubleshooting on configuration issues, you are better served by our regular Technical Support, as they have got the tools to access your system remotely, if required, and can also escalate the issue to the product developers, if need be.
Please do not hesitate to keep posting your questions related to programming and systems integration (from an architectural and design perspective) involving PI here in the vCampus forums.
I am trying to connect the PI tag to OPC client which is Timestamp tag.. but PI OPC client shows the error "unable to add item to group: Additem returns Generic Failure".. Is it due to that PI OPC client don't support the Timestamp data type or due to some other error?
Seems like that would be the case. If you refer to the Supported Features in documentation of PI OPC DA\HDA Server. You will find that Timestamp is not listed as a supported PI Point Type.
The best person to comment on this would be the developers for PI OPC DA\HDA Server. I'll reach out to them and see if they can confirm this.
Han Yong is correct: the PI OPC DA/HDA Server does not support PI Points defined with type 'Timestamp'.