2
Is this the same as eCal v 2.24? What version of XOOPS do you use? eCal says it is for XOOPS version 2.0.13 so if you are using a version of XOOPS that isn't a 2.0.13x version then it may not work properly.
Have you checked the calendar module admin(if any) to see if there is a setting for a theme? Some modules come with there own theme(s).
Quest