Internal Server Error whilst Importing a CSV File?

Hello,
I've getting an internal server error message when trying to upload a CSV file via Products > Import.

Can anyone suggest why this is happening or help at all please?

The site was in a test folder before going live and the import worked fine. So it's only been moved to the main root.

Any help would be much appriecated!

This is probably a limitation set on your script. Can you post it here please?

It's indeed probably happening because the resource limitation is too strict on your website for the file you're importing.
In that case, you can split the file in several smaller CSV files.
Or increase the memory_limit max_execution_timeout options of your PHP.

It could also be that the CSV file you're using is not valid.