The "bad robots" rule (id 990012) contains a line that blocks all traffic with an user agent containing the string "Windows XP 5". However, each and every Java applet that runs on a Windows XP machine has a user agent string that looks like this: "User-Agent: Mozilla/4.0 (Windows XP 5.1) Java/1.7.0_13".
That means that this rule kicks out everyone connecting with a Java applet from a Windows XP machine. This is surely not the correct behaviour, so the rule should be fixed to either not block user agent string that contain "Windows XP" or, that it only blocks traffic where the user agent string contains exactly "Windows XP 5". I.e. not with a "." following it.
Updated v2.2.8 to remove this signature.