Wrong Data Type for my Python Script Tool?

I've got the following script and want to run it in the ModelBuilder.

import arcpy, os
dem = r'C:\folder\dem.tif'
out_folder = r'C:\outfolder'
epsgs = range(32601,32661) + range(32701,32761)
for epsg in epsgs:
    print 'Reprojecting to epsg: ',epsg
    arcpy.ProjectRaster_management(in_raster=dem, out_raster=os.path.join(out_folder,'Reprojected_epsg_{0}.tif'.format(epsg)), 
                                  out_coor_system=arcpy.SpatialReference(epsg))

So I've changed the input and output this way,

import arcpy
import sys
import string
import os

dem = arcpy.GetParameterAsText(0)
out_folder = arcpy.GetParameterAsText(1)
epsgs = range(32601,32661) + range(32701,32761)

and loaded it into my toolbox

Here is the 1st problem. Did I have chosen the wrong Data Type? I want the script to save the created files into the existing folder.

Then I tried to write another folder to the path and the error disappeared.

Y:\Home\hoffmada\World_rivers\Verarbeitete_Daten\Flowdirection_UTM_120\flowdirection

But when I want to execute the script I got this error message.

So what Data Type do I have to choose to write down the new rasters into my folder I've chosen?