4.7 Woes - Call to undefined function module_list()

It seems that either the event or calendar module completely freezes up this website I manage...Every time I enter a new event I cross my fingers...but, alas I am stuck again. It seems my shared hosting database is ok and I have backups...but, some module or something always wacks things out...I would love to upgrade to 6.0 but have no idea how well that would go.

So, I have a dev sub folder that I have put everything....I tried deleting this module and that module and then I just uploaded the original 4.7 package...and, this is what I get...

Fatal error: Call to undefined function module_list() in /home/*********/public_html/dev/includes/install.inc on line 12

If it is not that error message it reference a module. I delete that module and it generate the same error for another module.

What should be my plan of attack?
Thanks in advance.

PS...I have had this site up for about 3 years....and, other than this one little bug, it has been a great website with low maintainance. If, in fact it is the calendar option, I might just drop a google calendar instead...

PS.....here is another error message: Fatal error: Only variables can be passed by reference in /home/******/public_html/dev/modules/search/search.module on line 926