Select_frame("relative=???)

Selenium IDE records a frame change as a selectframe|relative=up||. Now, this works perfectly if I am re-running the script from IDE in firefox. But if I export the same script in Perl and then try running in IE or Firefox (in proxyInjection mode), I get stuck at the point when the method 'select_frame_ok("relative=up") is called.
I look thru the Selenium document and came across this -
"...
To select the parent frame, use"relative=parent" as a locator; to select the top frame, use "relative=top".
..."

No mention of 'relative=up'...I decided to give 'parent' a try - select_Frame_ok("relative=parent") and script did move forward without any issue this time around... :)

-V.