DayPilotPro v7.7.3054
The new cellWidthSpec="Auto" setting causes a script error in IE7:
SCRIPT87: Invalid argument.
File: WebResource.axd, Line: 1, Column: 92919
The affected code appears to be:
this.maind.style.width=(this.$7O())+"px"
The error prevents the scheduler from being shown.
In IE8 or higher, this error does not occur.
This problem can be reproduced on your demo page:
http://www.daypilot.org/demo/Scheduler/AutoCellWidth.aspx