[!now] error message whenever I try to export files

this error message has randomly started happening since i updated illustrator. I have done a clean windows install and it still happens. All I am doing is trying to export designs at 300dpi as a png. I cannot export anything now. And as a work around I have to copy the designs to photoshop and export using that. However I don't like this option as the file is not a vector anymore. I have searched the internet everywhere and can't find anyone with this issue. Please HELP
