Site seems down with a white screen error and not sure how to fix it

[wynnyelle]

So there is a white screen error that says this:

Fatal error: Call to undefined function blog_override_default_actions() in /home/develop/public_html/index.php on line 263

This is a testing site environment so I replaced the file it talked about with a new file fresh from the live site which works fine right now. It did not fix this.

Please be kind...I want to fix this myself, I just don't know where to go from here.

[margarett]

You probably installed or uninstalled a MOD with errors. Now, what did you do?

[Kindred]

And randomly replacing files is a sure route to digging your hole even deeper

[wynnyelle]

It turns out that the database is missing most of its tables, for some odd reason.

Creating them now to see if that fixes the issue.