This issue is related to the localized version of the StyleWriter II driver v1.2 included with the German System 7.5 software.
In order to print using a PowerBook 150 and the German version of System 7.5, you need to use the StyleWriter 1200 v2.1.1 printer driver.
Note: This issue can occur on other Macintosh computers as well.
Since the German localized StyleWriter 1200 v2.1.1 printer driver is backward compatible and included with the German System 7.5 software, you can and should use this printer driver.