If you haven't, try to use it via 000webhost.com Members Area, below Useful Stuff group, you should found a feature called 1-Click Website Restore. Read the instructions given, and you've uploaded all files needed by your website only in 1 click (and lossless)!
What kind of errors? Have you checked the modx documentation for advice first and are certain you have entered all the required information correctly? Check and double check and then post the error messages you are getting.