If you are not able to upload your file, it is most likely due to the file type or the file size. PrintingCenterUSA prefers files to be uploaded as a PDF but accepts the following file types: PSD, AI, INDD, PUB, TIFF, JPEG, and EPS.
If your file is larger than 2 GB, you will most likely have difficulty uploading your file. You will need to break your file into multiple files and upload separately.