Once we got the build, we need to execute all the test 
cases in Test Summary Report. If any test case fails, then 
we need to submit the bug in bug-tracking tool. After 
completion of execution of all test case execution, we need 
to send the Test Summary Report to the Dev. Team. By using 
the Bug Tracking tool and Test Summary Report Dev. team 
knows what are the scenarios the application fails.

Once you ve found a bug, its either be the first or 
fifth... U immediately report the bug in the bug tracking 
tool and based on its severity u ll proceed with the 
testing.. If it is a show stopper then U cannot proceed 
with testing ur 6 th test case. So it should be fixed 
first. If it is not a show stopper U ll giv it to the 
developer for fixation and proceed with testing the other 
test cases and mark the untested cases due to the impact of 
the bug in 5th case as UNTESTED CASES IN ROUND1.

When you are executing the test cases then you have to 
pass/fail the test plan for the corresponding test case 
according the true execution performed by you. So, in the 
case when it fail/pass you have to report the same. It 
doen't matters what the stage it is.......; this decide the 
status of the bug only. According to this you state the 
severity and priority of the bug and make entries in the 
tracking tool.
Definitely it is the application error in that module, 
provided you have execute the test cases very carefully.

while executing the testcases,if 5 th test case of 10 
testcases is failed,then we need to focus on the type of 
test case like whether it is a high priority test case and 
is the testcase is dependent on remaining testcases.

Let us assume,if the testcase is dependent on remaining 
testcases,then the priority is very hidh,becasue it is a 
blocking issue.
If it is not dependent on the remaining testcases,based on 
the nature of the bug immediately log the bug with  proper 
priority and move on to the execution of the remaining 
testcases.

Correct me,if I am wrong...

if any test case fails during the execution, go and report 
a defect in the defect tracking tool. It is irrespective of 
test case and Application.

Some small scale companies doesn't mantian Bug Tracking 
tool, In such case testers will be maintaing the bug 
reports in Excel sheet, As pervious answers if the bug is 
show stopper report this excel bug report to the dev team 
or to your team leader , get it fixed , give the dev team 
full details with snapshots of the bug and also who to 
reproduce at dev evnvironment.