You've created an REW biquad output, copied and pasted it to the plugin and now getting the following error: 

Warning!! Error input: Missing biquad value(s). 

The biquad configuration was most likely corrupted and solving it will involve deleting your configuration to start from fresh. PLease do as follow: 

a) Close the plugin

b) Navigate to the Mydocuments - > miniDSP  - > plugin name

c) You will see a settings.xml file. Please delete it. 

d) Reboot the plugin and you'll be able to configure your unit correctly.