Hi Adrian,
Nice detective work.... I talked to the Deploy team and they have not heard of this being reported by anyone so one more quick test. If you install just the German language and not English does that work?
Since you are using BOE can you log a case in Service Market Place ( https://support.sap.com ) and select BI-BIP-DEP for the component.
And include the install logs showing the error with those dll's.
Thanks again
Don