How to fix an error you can't reproduce?

[surfbird0713]

Just a general question - how do you try to fix an error you can't reproduce?

Some users are reporting an error message in IE on my client's website, but I am not able to reproduce it. I've checked multiple computers in IE7, 8, and 9. I see the error if I go to browsershots.org (website is cookware.lecreuset.com if you want to see for yourself), but can't get it to come up for real.

I have one idea of what the problem could be, but I don't think browsershots will not be able to access the testing site where I can troubleshoot (it is IP restricted). If I'm wrong about the problem, then "as the tree said to the lumberjack, I am stumped".

Anyone have any tips/tricks they use in situations like this? I am away from all my files so I have to wait for the morning to actually work on the issue.

[NickJohnson]

Did you solve that problem???????
How did you do that??????

[kevin619]

Fixing Bugs - if you can't reproduce them, you can't fix them
"Generally, if you can’t reproduce it, it’s almost impossible to fix". Anonymous programmer, Practices of Software Maintenance, Janice Singer
Fixing a problem usually starts with reproducing it – what Steve McConnell calls “stabilizing the error”.