It depends on what type of upload your trying to increase.  For photos go to admin panel  and go to settings -> usersettings -> content input and you can adjust the photo upload there.

If you have a video upload plugin, check the settings on that plugin, i dont have one but that is a good start.  This also goes for the forum check plugin settings.

Otherwise you can adjust the max upload attribute of the server in two ways.

In htaccess add the following;  this will take care of the post size and upload size, change the 174 to whatever you want.

php_value post_max_size 174M
php_value upload_max_filesize 174M

Or you can change it in your php ini file   (sometimes this works sometimes it does not depending on the server set up) (if not your htaccess in combo with this will work)

in your php ini put this, again change the 174 to whatever you like

upload_max_filesize = 174M
post_max_size = 174M

in both cases make sure it does not already exist in either file before adding either

Also please at least attempt a search as this has been discussed many times.  

Hope this helps you... happy coding :)

Quote from allyn I have the same exact problem on Arvixe.  Can you tell me exactly how you solved it?