If you get any of the following target server error messages:

Error: rpccore backend client Unable to receive
Error: rpccore backend client Procedure unavailable
Error: rpccore backend client Remote system error
Error:rpccore backend client Client can't decode result

Or the following Tornado Warning dialog:
Target Server "111.22.333.444@XXXXXX" is not responding.
This may be due to slow network response.

It means there is a problem with your Core File and Symbols.

• Make sure your BSP files match up correctly. (i.e. same version of BSP)
• Also the file should be on a local drive
• Ensure full path

fromhttp://csg.lbl.gov/pipermail/vxwexplo/2003-July/002543.html:
Check the target server properties by doing Tools->target->Configure.

See Frame with Name -> target Server properties. In the combo box,
choose target Server File system , make sure that Enable File system
is checked and value in Root is C:\ or whatever is ur directory.

Select Core File symbols from that Combox box and make sure that File
textbox contains full path of vxWorks image you are trying to load.

Also if you have started FTP server, ensure that loggings are enabled.
Somwhere in Options of FTP server window.

Fromhttp://sysadminforum.com/t59460.html
This is the mismatch of files what you are running on your target and
what you specified in your target server settings. check if you have
the same vxworks image running on the target, which is mentioned in
your server settings. If not not, download it to target, run it, and
reconnect your target server once again, and you should be fine. I
hope it helps.