Error during resource binding. Session not found

We are using OpenFire 3.6.4 with BOSH. We have noticed when our MUC gets to about 150 users, other users cant log into the chat. We see this in the error logs:

2010.11.03 16:14:25 [org.jivesoftware.openfire.handler.IQBindHandler.handleIQ(IQBindHandler.java:59 )] Error during resource binding. Session not found in [e7195928, fcbf3f11, ad73712, 7c1fe9c3, e433233e, 971447a2, 51ed6e04, 9721a0d5, e6b96ba9, 61d387e9, c938f408, 9813668f, 6434044a, d0d525cc, efa2cdb2, d9461915, bdabc5d7, 12c833ee, f51766bc, b95e1d8f, eaff5b25, 98391b7e, 2f1b703f, ee036ae, 7d1fcc22, bb3eb3b7, c2c2b911, beedfabc, 2bbaa57a, 801eb436, e1219931, de41cec4, de2a3586, d3367a9, 16fce488, b5518a29, 462ef472, 522bbc78, 71ebba2d, 80b13e74, 8d3114ea] for key chat.involver.com/1c994427
2010.11.03 16:15:08 [org.jivesoftware.openfire.handler.IQBindHandler.handleIQ(IQBindHandler.java:59 )] Error during resource binding. Session not found in [6bbe36c0, 68d98319, fcbf3f11, 12f5c4f5, 82e40451, 61d387e9, 85048a64, 2cd906, 1343fd3e, 328380ea, eb429a92, adae54b6, 249354e, d4b556e7, 3c9e697b, c81bbbbe, 54b93783, e1dbd837, bb3eb3b7, d9d78adc, c2c2b911, 20a16370, cbe7fec9, 2bbaa57a, de41cec4, de2a3586, 16fce488, e43a2438, 462ef472, a02636bb] for key chat.involver.com/5c709732
2010.11.03 16:16:08 [org.jivesoftware.openfire.handler.IQBindHandler.handleIQ(IQBindHandler.java:59 )] Error during resource binding. Session not found in [1d542afe, fcbf3f11, 5eaf6c0, 6b5b050e, 82e40451, da257463, a185cc98, 750b68f8, b26807b0, 61d387e9, d5a9a1bc, f6d35f83, 7e042cb, be0a65a7, f4f10be, 249354e, 9c68798, df8a8ce9, 30ee166e, 61315983, 64a73ea0, 3c9e697b, bb3eb3b7, c2c2b911, 25cac6e3, 28b10f10, 2bbaa57a, 96a530e9, de41cec4, de2a3586, 533e5d36, 450232a, bff4060d, 16fce488, 129676cb, 462ef472, 8b7caa38, f272e78f, aed6f769, 561e49ac] for key chat.involver.com/448ff663
2010.11.03 16:17:02 [org.jivesoftware.openfire.handler.IQBindHandler.handleIQ(IQBindHandler.java:59 )] Error during resource binding. Session not found in [fcbf3f11, 50fdbe79, 981a379d, 6ae57839, f130445b, 82e40451, 334ebd87, 7695efdc, 61d387e9, 4dbee51d, 2fc0561b, 9e3acc64, 412e2307, a36dcfeb, a46d1c51, f4f10be, 7fdb64bb, 249354e, d9b489b9, 1f0dee9e, 30fa8b5f, 18ee366f, 3f871054, dfdffede, 434acc5f, ce79f466, 3c9e697b, 574de71e, c8fdf91d, bb3eb3b7, c2c2b911, 1fd5f47d, bd1ce475, 2bbaa57a, 5467dcad, de41cec4, de2a3586, e351f880, 16fce488, 462ef472, 6d975d3f, 7e34e318, 1ee9b020, bc40ed25, e6929647, 561e49ac] for key chat.involver.com/34e2dbb1

At first we thought it has something to do with user’s connections timing out, but we changed that setting and we’re still seeing this issue. Does anyone have any leads on this?