My CAD person prepared a DGN file, which I converted into a geodatabase. From there, I exported the points, polygons, and lines to a shapefile. The coordinate system is WGS_1984_World_Mercator Meters. I need to get these files into Zone 901 Datum NAD83 HARN. I am assuming that the HARN they want is in feet, but I'm really not sure. So I'm doing it in feet anyway. I am using the Project tool in Arc Toolbox, but I get an error message saying "invalid extent for output coordinate system".
I should add that I also tried setting my workspace to HARN feet, bringing the geodatabase in and doing an export to a shapefile choosing 'use data frame coordinate sytem', and it shows it works, then if I do zoom to layer, I can't see anything.
It's very possible that the original coordinate system information is incorrect. That error message about an invalid extent, is usually due to data with incorrect coordinate system being projected to another coordinate system. Because the coordinate values don't really make sense for the input coordinate system, they end up making even less sense in the target coordinate system!
Go back to the original data and check its extents. Do they look projected or geographic (latitude-longitude)? If projected, add to ArcMap and change the data frame's display units to decimal degrees (general tab of data frame properties). Do the numbers make sense? If they don't, then it's confirmed that the coordinate system is incorrect.
You'll need to double-check with your colleague about the coordinate system--it's not in state plane or UTM? Otherwise, post its extent here and maybe someone can figure it out.
Given the error message, I would first check to make sure that the data I believe to be in Mercator actually is. Comparing it's position to other Mercator projected data is a good first step. Next, does the data indeed fall in a region appropriate for that zone of your target projection?
Can you successfully project the data to other, similar coordinate systems?
You write that you cannot see anything; are there any rows in the attribute table? Does the preview in ArcCatalog show any features?