Here's a generic patch that works for the last few releases of Incredimail 2001 and will probably support some of the later ones.
Install Incredimail first and before you apply the patch, make sure it's shut down (including its icon on the taskbar).
The patch comes in two parts.
If you're on a dial-up connection you only need to apply Incredimail_patch.exe.
If you're on a LAN you must apply, in addition, Incredimail_extra_patch_for_LAN.exe.
You can copy the patchers in Incredimail's \Bin directory and run them or just point the patchers to it.
Have fun and then go buy it if you like it.
roocoon