Warning: file size error

I have installed the gk stocks module on to a site and when enabled I continually get this error:

Warning: filesize() [function.filesize]: stat failed for /home/e/s/domainaccount/public_html/joomla/cache/mod_stock_gk4.data in /home/e/s/domainaccount/public_html/joomla/modules/mod_stock_gk4/helper.php on line 94

The stocks chart shows up file but the warning message is always shown above it.

If I look in the cache directory, there is no 'mod_stock_gk4.data' file.

Please disable display_errors option in PHP configuration which is recommended by Joomla installer.

Hi,
How do I do that?
I don't have access to the php ini file as I am on a shared hosting.
Is there something I can add to the htaccess file?
Thanks