A family of Microsoft spreadsheet software with tools for analyzing, charting, and communicating data.
Try
=COUNTIF(INDIRECT(INDIRECT(ADDRESS(4,5))),"x")
Note:
As the help says, INDIRECT "returns the reference specified by a text string. " The text string should result in a RANGE ADDRESS.
So (INDIRECT(E4) will give you a REFERENCE to range $B:$B as E4 contains string $B:$B
INDIRECT(ADDRESS(4,5)) will give you a REFERENCE to range E4 as ADDRESS(4,5) evaluates to E4 and since E4 contains $B:$B, the final result will be the string $B:$B.
To get a REFERENCE to range $B:$B, you have to again wrap it in INDIRECT.
Hope this clarifies.