If you got an export and you get errors on importing, then I'm assuming you are getting dependency errors. Which basically means that the export you have might not contain all the information you need, and from that point of view, it might be useless.
When using Content Porter I always stick to one simple rule; know what you are trying to accomplish.
This means you have to be very aware of what you export and how you can import that again. First things you need to be aware of is that you need to export all relevant content. A Component is based on a Schema, resides in a Folder, which belongs to a Publication. So you need all those items (and their dependencies) to be able to correctly import that single Component. When BluePrinting comes into play, that just multiplies the number of items you require (parent Publications and their structure etc.).
Also be aware of what I like to call the chicken and egg problem (as explained here).
When all that is taken care of, then know what you are importing, and be sure to select the resolve with BluePrinting mapping option if required (which means you need to have the Parent items in the export also).
So simply put, if you just get an export with the instructions; import this. You are bound to come across issues you can not solve. It is in my opinion better to make the export together with your client so you know what is exported and you know what to import and how. To make this whole process more manageable, it is most of the times better to do small exports. So export the structure first (Publications, Folders and Structure Groups), then the Schemas and last the Content. Import those three exports in the correct order and you should see it all goes painlessly.
In the end you should see that you can export and import everything without having to do anything manually. It is even possible to do that in one step, with a huge export and huge import, but most of the times it goes a lot smoother if you break it up in smaller (manageable) steps.