I'm having a puzzling problem including a LaTeX equation in a post. I have it in a sample post (HTML below), and it works fine. I cut and paste the '$latex ... $' portion into another, longer draft, and I get "Formula does not parse". If I then cut and paste it from the second post (where it didn't work) back into the first (where it did), it works again.

Here's the complete first post:

```
<br />
Here is some text stuff:<br />
$latex s = \sqrt{ \frac{\sum_{i=1}^n (x_i - \bar{x})^2}{n-1} } $<br />
Some more stuff<br />
$latex s = \sqrt{ \frac{\sum_{i=1}^n (x_i - \bar{x})^2}{n-1} } $<br />
```

Does anyone have any suggestions about what might cause this?

The blog I need help with is richg74.wordpress.com.