Please share the following so that I can understand the situation better:
1. The snapshot of the error that you are getting in EZ USB Suite.
2. The snapshot of the window obtained when you do the following:
Right click on project -> Properties -> C/C++ Build -> Settings -> ToolChain
Also, please let me know which firmware you are using.
This issue was solved just now.
Thank you for your response quickly!
Glad to hear that the issue is resolved. Please let us know how you managed to fix this.