Error when clicking edit/view order

Warning: fread() [function.fread]: Length parameter must be greater than 0 in /home/brockha1/public_html/system/library/cache.php on line 27
Fatal error: Allowed memory size of 67108864 bytes exhausted (tried to allocate 5628141 bytes) in /home/brockha1/public_html/system/library/cache.php on line 43

I am getting this error when I click to edit/view any of my orders. I'm sure I haven't changed any of my settings. Does anyone have any ideas what it can be.
Thanks
Stewart

What PHP version are you using? Seems there's problem with php fread() function.

As far as I'm aware it's the latest version

Do you know how to sort it. Why would it just start doing this all of a sudden.

Thanks for your help so far
Stewart

Do you allow read/write permission to cache folder in /system/cache ? I don't know but i just guess function fread() could open cache file due to file/folder permission issue.

you need to add

php_value memory_limit 32M

to your .htaccess file
Same was happening to me.

where do i enter that line, i just put it at the bottom of the .htaccess file and it caused an internal 500 error on my server, put it in my php.ini files and it made no difference.

have anyone solved this problem???
same thing happening to my site now, any solution, thanks