@RajalakshmiP Generally speaking, when calling PerformClick on a control does not work as expected, I look for three things;
Do I have the correct control interrogated? I use SelectElement to grab the controls around that area and make sure that I have selected the correct one.
Do I have the correct control matched? I would ensure that the match rule(s) for the control are correct and that there isn't any ambiguity in what is being matched anywhere in the hierarchy.
If neither of these work, then you may need to examine the page in further detail to determine which events you might need to raise. I generally start with calling the OnKeyUp, OnBlur, OnClick events to see if those three trigger the click.
Are you able to post the HTML of the control (its parent or its grandparent would probably be more helpful or even further up in the hierarchy)?
This is the HTML part to upload a file.
<div class="labelContainer"><label for="Src_File">File Name:</label></div><div class="inputContainer"><input type="file" name="Src_File" size="45" maxlength="80"></div>