My system:
Lenovo Thinkpad T420
Intel Core i5-2520M (2.50 GHz)
8.0 GB RAM
Windows 7 Ultimate 64-bit SP1
Reaper 5.03 x64
The crash happened in 5.02 x64 as well. (I haven't tried the plugin in earlier versions of Reaper since I just started using this plugin.)
It's a freeware download:
http://www.ddmf.eu/plugins/ColourEQWin.zip
The crash happens when trying to change the color of the foreground or text of the plugin (using the "colour" option in the top left).
Procedure:
-start Reaper 64-bit
-load a track
-load the ColourEQ 64-bit plugin in that track
-hit the "colour" button, try choosing the top selection (foreground)
Windows error report:
Faulting application name: reaper.exe, version: 5.0.3.0, time stamp: 0x560426cf
Faulting module name: ColourEQ_64.dll, version: 0.0.0.0, time stamp: 0x4e9d426f
Exception code: 0xc0000005
Fault offset: 0x0000000000091e67
Faulting process id: 0x5cc
Faulting application start time: 0x01d0f73235e7f1f9
Faulting application path: C:\Program Files\REAPER (x64)\reaper.exe
Faulting module path: C:\Program Files\VstPlugins\ColourEQ_64.dll
Report Id: 79b609db-6325-11e5-b39d-e77844526763
This function works fine in the 32-bit version of the plugin (bridged, in Reaper 64-bit, on the same computer).
I don't know if this is the plugin's fault or not. It's quite possible.
I'm honestly not concerned if I can't alter the color of the plugin but I figured I should mention this if there's something more serious going on than that, since I like the plugin.