[1.16] I cannot upload big dump files (memory, http or timeout problems). Starting with version 2.7.0, the import engine has been re–written and these problems should not occur. If possible, upgrade your phpMyAdmin to the latest version to take advantage of the new import features.
The first things to check (or ask your host provider to check) are the values of upload_max_filesize, memory_limit and post_max_size in the php.ini configuration file. All of these three settings limit the maximum size of data that can be submitted and handled by PHP. One user also said that post_max_size and memory_limit need to be larger than upload_max_filesize.