You've probably arrived at this page when you'd rather be at the colorblind web page filter working to make your site more accessible to color blind users. Unfortunately, the server load has gotten too high and so you're seeing this error.
The color blind web page filter has been growing in popularity and this has been putting a high load on the web server. This server is shared with other pair.com customers, and it isn't fair for me to hog all of the CPU, so the system administrators have probably removed the executable bit on the filter script.
Update (12 March 2003): Last weekend I removed features in order to make the script more server friendly. I removed jpg and png filtering (you get back transparent gifs instead), removed handling of large files (over 75K), and started ignoring files based on certain file extensions rather than inspecting the content of the file to see if it was filterable but just had an unusual extension. As a result, the service ran within acceptable limits... for a few days. The number of users is still increasing, and it turns out that this reduced functionality is still too taxing on the server for the number of users. I have some ideas about further reductions in functionality which I hope to put in place the weekend of March 15/16. Instead of processing all gif images, I'll only process those which appear to be web site "chrome", for some heuristic sense of the term. I'll probably handle image tags which have specified alt attribute values of the empty string, only whitespace, and maybe a few regex patterns (to match 'shim', 'spacer', 'background', and that sort of thing). I hate chopping off all this functionality, but it's either reduced functionality for everyone, or no functionality for anyone. (But see below about how you might be able to help.)
Update (17 March 2003): Sorry folks. Between trying to buy a house, find a job in another state, and having company in town there just wasn't any time to work on this. I'll hold off on making any commitments until I have a job and a house lined up. After that, this can become a higher priority again (until we're in the midst of moving).
Update (7 April 2003): Pair.com has graciously offered to donate a dedicated server to host the colorblind colorfilter. We're in the process of working out the details, although at the moment my hectic schedule is the most significant obstacle. I hope soon to have the filter up and running. You won't need to update your bookmarks as http://colorfilter.wickline.org/ will 'just work' once I get things up and running on the server. If time permits, I'll have it running under mod_perl (which pair.com has installed on that server) for increased efficiency. I'll probably start it out with the reduced feature (from March 12) to test the waters. If the server holds up well, I'll try re-enabling some of the features I'd had to chop off previously.
Unfortunately, you're in a bit of a pickle right now. Your best bet is to just try again in a little while (try in 15min, then an hour, then a few hours, then tomorrow). If you were using the color filter, Vischeck has a similar service which you can use in the mean time. I find it less fun to use (or I wouldn't be doing this), but my opinion may be prejudiced, eh? This discussion at the Signal Versus Noise web site includes mention of a JavaScript bookmarklet which allows Windows MSIE users to apply a grayscale filter to the current page. Just copy the JavaScript URL into personal toolbar bookmarks and click that link to turn the active page into monochrome. This will work as an adequate test for most forms of color blindness. Note: you can also just switch your display to 256 grays or some such (which doesn't require MSIE for Windows).