Can someone please help me with this problem that I'm having with report generation trying to log excel data?

[GRCK5000]

How do I prevent these errors from happening. I have attached my code. 

Error 1 below usually occurs when I'm trying to close the excel while data are being logged.

Error 2 below usually occurs when the previous file with the logged data is still open and  I'm trying to run a new test.

Is there any way I can prevent these errors like creating new file before every run.