problem with uploading large files

[eluser]ebuoe[/eluser]
hello i've been unable to upload files larger than 1mb ... n i have these settings in my php.ini
post_max_size = 100M
upload_max_filesize = 100M

and i even increased the max_execution_time and max_input_time
it shows me this message "The file could not be written to disk"

what could be the problem any help would be appreciated

[eluser]InsiteFX[/eluser]
How many forum topics are you going to post this in?

InsiteFX