Raj,
As Gennediay mentioned, I think you're best bet is to code an OnLogError event handler so that, when an error is logged, it will still send the e-mail. You can also look into using OnStopTest event handler as well.
Basically, what Irina, Gennadiy and myself are trying to say sums up like this:
Sub Test()
RunLine1
RunLine2
RunLine3 <-Error occurs here
RunLine4
RunSendMail
End Sub
If your test code looks like what is shown above, when the error occurs, nothing after that error will run. Script code is run in sequence and so if there are any errors that cause the test to stop, it will not just fail the line but will fail the whole subroutine and skip any additional tests. This holds true for Keyword tests as well. Additionally, if you're using Test Items to organize your tests and there are 5 test items, the fifth one being your SendMail, if Test item 3 fails and the "Stop On Error" is set for that item, no other items after that will run.
It's a matter of making sure you write sufficient code to be able to handle unexpected failures. So, Event Handlers is one way... you can also, in VBScript, us On Error Resume (I wouldn't recommend it personally). If you were using a different script language (like JScript or DelphiScript) they have try/catch/finally logic that will allow you to trap exceptions and execute code for them.
There's not some sort of "special" way built in to TestComplete that, on error, automatically e-mail the log file so your best bet is to use the OnLogError event handler for the "easiest" way to handle this particular problem.
