Thank you for sharing the issue you are faced with us.
I kindly ask you to send us a bug report with attached log files directly from the IDE right after the issue would be reproduced. This option is present in the menu Help -> Report a Bug. Also, may I please ask you to write the full path of your project in the bug report? You can easily get it using the option 'Copy full Path' by right click on the name of any opened file in the code editor.
Also, can you please tell me what name do you use for your new Anonymous Apex file? Is it possible to create the file using the default name which is provided by the IDE?
In addition, we will appreciate if you can provide us with a screenshot of the error.
Can you also tell me, if pulling of files from your Salesforce Org fails with the same error?
All this information will help us to find the reason for the issue, and will have an ability to solve it.
Thank you greatly,