Ah NTFS. NTFS support is deprecated starting with 4.2
core.gz is not able to mount cde on NTFS to continue loading. However. the cde directory should only reside on iso and not be copied to any hard drive. Adding the X/GUI extensions to where your normal TCE directory resides will solve your issue, and is the expected location. This way individual updates to the X/GUI will occur as for any regular extension.