Hi Kyle,
A couple of potential issues spring to mind
1) Check the CSV file is well-formed with the correct number of records on each line.
3) Check your PHP configuration in case file uploads are not configured correctly. From INSTALL.txt:
8. Setting PHP variables
There are some PHP configuration variables that may need to be customised, depending on your needs. The variables that are commonly changed
include "memory_limit", "upload_max_filesize", "post_max_size", "max_input_vars" and "upload_tmp_dir".
memory_limit - This will need to be increased for restoring large course backups or unzipping large files within Totara
upload_max_filesize - This setting in conjuction with "post_max_size" will determine how high you can set the max upload size within Totara
max_input_vars - This setting will need to be increased to a minimum of 2000 if you would like to customise any of the Totara language packs.
upload_tmp_dir - Some customers may wish to enable this setting and specifically set a directory where files are temporarily stored during the upload process.
Note the web server user must have permissions to write files in this directory, or all file uploads will fail.
These settings are all located in php.ini. See http://php.net/manual/en/ini.core.php for more information (note that you will need to restart your
webserver for these settings to take effect).
If your CSV file is very large you may need to raise the settings in "upload_max_filesize" and "post_max_size". Also check the upload_tmp_dir is writable by the web server.
Finally you could turn on debugging and see if you get more detailed error messages which might narrow down the exact problem:
Site Administration -> Development -> Debugging page, set "Debug messages" dropdown to DEVELOPER and check the "Display debug messages" checkbox, then try to upload the CSV file again. Remember to turn set Debug messages back to NORMAL once you have a screenshot of the detailed error message.
Hope this helps
