keyboard shortcuts stopped working , especially for control and shift keys for 10.6 (snow leopard)

My application has many keyboard shortcuts like Shift + Command + X and Ctrl + Command + R, which are working nicely on 10.5 (Leopard).

However, when I run the same application on 10.6 (Snow leopard), these keyboard shortcuts don't work. C开发者_如何学运维an someone please tell me the reason behind this?

In addition to my comment i post an interessting paragraph from snowleopards FAQ:

I read that Snow Leopard includes a typing shortcuts (text substitution) feature, but I can't find it. How to I turn it on? In System Preferences, click the icon for the Language & Text pane in the top row (known as the International pane in Leopard), and then click the Text tab. The scrolling list on the left includes a number of default text substitutions (to turn (c) into a copyright symbol, for example), some of which are turned on by default. Click the + button at the bottom to add new substitutions of your own, and click the checkbox next to each item to enable or disable it.

Note that this list is global -- there is no way to create application-specific substitution sets -- and it is currently only used by a few applications, such as TextEdit and Mail. In those applications, substitution can be turned on and off for all documents or for individual documents. 

This Paragraph can be found here: FAQ