"Computer is being used from another location" (it isn't)

Acronus Online Backupis no longer working, although initiallu it did.
I now get an email message:
"1 Information 10/10/2010 01:31:03 Operation Online Backup started.
2 Error 10/10/2010 01:31:05 The certificate is not valid. Probably this computer is being used from another location. Please reconnect to the online storage to update your certificate.
4 Error 10/10/2010 01:31:05 Operation has completed with errors.
I have tried logging on to the online backup site, but to no avail.
Help please!
Philip