Many bugs in the SCI1 games did not surface until the PCs got faster. This was the case, even when the games were still relatively new. The timer bugs manifested themselves in a variety of ways, from crashes with or without error messages to endless loops or events not being triggered. Sierra released patches for some of these errors, but some errors did not surface until PCs got fast enough to trigger them. The older the game was made it less likely that Sierra would release a patch. Often, older games that they still supported, only had save games as a work around. There are a handful of fan made patches to address some of the most infamous the timer bugs, but these sometime introduce new problems.
Playing the games in DOSBox addresses these timer issues. It can simulate a machine of the speed that the games were originally designed for. The new installers here are the best way to go to play the games on modern PCs. http://sierrahelp.com/Patches-Updates/N ... llers.html
For the DOS games, they will automatically set the games up in DOSBox, apply all relevant patches and properly configure the game and DOSBox to optimal settings. The games can be started from a Windows shortcut (like any native Windows game) with a high res icon for Vista/Win7. The DOS games come with a configuration utility to make it easy to adjust DOSBox to your preferences.
The Windows games have even more issues. In general, the SCI Windows games were considerably buggier than their DOS counterparts. IN addition to the timer bugs, antiquated APIs create problems on newer versions of Windows. Many of these games were 16-bit and or came with 16-bit installers. Most 16-bit code will not run on 64-bit Windows. Only certain InstallShield 16-bit installers will run, and for the most part, Sierra did not use IS for their installers. Some 32-bit games shipped with 16-bit installers. Game that do not need much more than to be copied to the hard drive are easy to deal with, but many are more involved. Some of these I have reversed engineered to create new 32-bit replacement installers. Some have required compatibility fixes, too.
Try installing the game with the PQ3 installer and see if you still encounter the problem. Just keep in mind that you may have to start the game over. The save games are very version specific and those made with a bug can carry that bug over to the new game.