when i tried to follow though on neptunesuzzy's tutorial step 4) Now, let's build our New Package
http://personal-computer-tutor.com/...clothingtut.htm

but i keep getting this error message when i use the tool-->object-->fix integrity

Object reference not set to an instance of an object. SimPE Version:
Default (0.73.44.37511).

Exception Stack:
System.NullReferenceException: Object reference not set to an instance of an object.
at pjse.FileTable.Remove(Entry key)
at pjse.FileTable.PFD_DescriptionChanged(Object sender, EventArgs e)
at System.EventHandler.Invoke(Object sender, EventArgs e)
at SimPe.Packages.PackedFileDescriptor.DescriptionChangedFkt()
at SimPe.Packages.PackedFileDescriptorSimple.set_Instance(UInt32 value)
at SimPe.Plugin.FixObject.Fix(Hashtable map, Boolean uniquefamily)
at SimPe.Plugin.FixTool.ShowDialog(IPackedFileDescriptor& pfd, IPackageFile& package)

Source:
pjse.filetable.plugin

Execution Stack:
at pjse.FileTable.Remove(Entry key)
at pjse.FileTable.PFD_DescriptionChanged(Object sender, EventArgs e)
at System.EventHandler.Invoke(Object sender, EventArgs e)
at SimPe.Packages.PackedFileDescriptor.DescriptionChangedFkt()
at SimPe.Packages.PackedFileDescriptorSimple.set_Instance(UInt32 value)
at SimPe.Plugin.FixObject.Fix(Hashtable map, Boolean uniquefamily)
at SimPe.Plugin.FixTool.ShowDialog(IPackedFileDescriptor& pfd, IPackageFile& package)

Windows Version:
WindowsXP

.NET Version:
2.0.50727.3603

please tell me what i am doing wrong

i guess no one can i already talked to SimPE forum and they told me to check here

Try the tutorials listed on this site. The one you're using looks a bit outdated and has some extra steps that you don't need. Try this one instead.

thank you

Hey, I had the exact same problem, here is the solution

edit:

right click on each gmdc, gmnd, cres and shape to clone them, delete the old ones, save then fix integrity.

it worked for me.

THANK YOU ....I have been pulling my hair out for hours over this