really confusing! fatal error for what??

[icd_lx]

I got a fatal error for using an "unsupported operand type", on this one line of code :

$last = $post + $posts2alter;

What could I have possibly done wrong!? In the script ive been working on, theres tons of lines like that, and none of them but this have caused a fatal error.

[icd_lx]

I did something stupid and absent minded, for the 20000000th time.

Ignore this thread.