i'm trying to import content from joomla into k2. but it seems like the process doesn't complete successfully...i don't get any error message but i get a blank page. I have to click the back arrow on my browser for me to access the K2 component home page. And when i check not all categories and articles are imported. i have more than 2k articles on my website. What could be the problem here

Could you please enable error reporting to see the actual error?
Error reporting can be enabled from Global Configuration/ Server tab.
Make sure you set it to development.

I have enabled error reporting and set it to development as you instructed. after clicking import the page displays a blank page. No error is displayed. I had even increased memory and execution time in php.ini file but seems that didn't solve the issue. On clicking back arrow on my browser i found out that some articles had been imported but not all of them. Finally i have been trying to update my 2.6.7 k2 component to 2.6.8 but i get path does not exist error. I though maybe the latest component might solve my problem.

The issue is located elsewhere.

You have probably either wrong folder/file permissions and wrong paths for your log and tmp folders.

If K2 could not be installed due to this, then you will not be able to install any other extension.

Go to Site-> System Information -> Directory Permissions and make sure your folder are writable and double check the path for Log directory and Temp directory.

My log and temp directories are both writable. Si i don't know whats the issue here.

Have you checked your error_log (you can ask your hosting provider to point you to it) for any issues?