Error: Linked market CO2 could not be linked to GHG

[licaicaicumt]

I want to set emission constraints in GCAM v.7, and three lines below are added to the configuration.
<！--net0 emission constrains>
../input/gcamdata/xml/dac_ssp2.xml
../input/policy/linked_ghg_policy.xml
../input/policy/ghg_net0_constraint_global.xml

emissions constraints.zip
The following error occurred：
Linked market CO2 in USA could not be linked to GHG
Linked market CO2_FUG in USA could not be linked to GHG
Linked market CH4 in USA could not be linked to GHG
Linked market N2O in USA could not be linked to GHG
Linked market C2F6 in USA could not be linked to GHG
Linked market CF4 in USA could not be linked to GHG
Linked market HFC125 in USA could not be linked to GHG
......
How should I modify it to achieve emission constraints?