> This works for me, cutting and pasting exactly what you have posted into a small org file.

You probably have "\\usepackage{tikz}" set in your variable
`org-format-latex-header' (another fix for the issue).

> Output from my *Messages* buffer:
> ,----
> | Wrote /tmp/x.org
> | org-babel-exp process latex at position 128...
> | Evaluate this latex code block on your system? (y or n) y
> | executing Latex code block...
> | (Shell command succeeded with no output)
> | Code block evaluation complete.
> | Local Ispell dictionary set to british
> | Saving file /tmp/x.tex...
> `----
> when I export to LaTeX.  What does your message log say?

Actually, the output looks identical when the command indeed fails to
run latex without errors - the output file is generated nonetheless and
the user thinks everything is ok. I'd suggest to add '-halt-on-error' to
avoid creating an output file. This will then signal an error to the
user. A possible patch is appended: