Selenium RC cant find locator

I have the following locator:

css=tr:contains('First page') + tr table td:contains('Yes') input

I can find it o开发者_开发技巧n the page using Selenium IDE, but my Selenium RC test fails trying to find it.

What can be the matter?

Try Using Fire bug to locate the element and then using the same try running the code in selenium RC. Many times the selenium IDE reads the location in Short due to which it fails try the above method.