Selenium Script which contain waitForPopUp command working in firefox not in Internet Explorer.

I am running Selenium script which contains waitForPopUp command. It is running properly in firefox but it does not opening the popup window in Internet Explorer.
I had made all the changes regarding popup window in Internet Explorer 9 (i.e disabling the Turn on Pop-Up Blocker).
I am using following Script
driver.findElement(By.linkText("Maintain Master Case")).click();
// ERROR: Caught exception [ERROR: Unsupported command [waitForPopUp]]
// ERROR: Caught exception [ERROR: Unsupported command [selectWindow]]
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Command | Target | Value
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Click | link=View Documents |
waitForPopUp | startFormWin | 30000
selectWindow | name=startformWin |
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It is working Properly in firefox, but it showing me Timed out after 30000ms in Internet Explorer.
I am new to selenium and would require your help to proceed.