The German installer was experimental and has errors that are fixed with the DOSBox installer. It is the most tested of the SHP installers. The 16-bit Windows Sierra games make use of the NTVDM, the highly flawed built in DOS emulator and WOW, (Windows on Windows), a 16-bit Windows emulator. This does not provide an ideal environmet for the old games. You are also exposed to other problems, such as hardware incompatibilities that can lead to problems like timer bugs.
You may have a slightly different version than the ones that were used to make the installer. When you use the DOSBox installer does it keep asking you to insert disc 1? Do you have the file "RESMAP.001" on disc one? Did you get this installer