Hi Michael, I certainly understand how frustrating this can be. Is there a pattern to what you were doing when the error occurs? Is it consistently reproducible? Does it happen on all campaigns or just one specific campaign?
If it is happening consistently and especially to more than one campaign, you most likely should contact Eloqua Product Support to log a case and have them further troubleshoot the issue for you.
Also, which browser and version are you using and which POD (instance) are you on?
Thanks. Hopefully we can get this resolved for you.