You should enable DNG in CHDK menu and then you can convert DNG even with ACDSee.
Thanks, I am now able to open the RAW files in photoshop.
So, back to the original question, is it possible to save JPEG version of the image without barel correction?
While not possible if using DNG, if you save images to your SD card in the camera's native non-standard-RAW format, then you could use CHDK's "RAW Develop" options to create a JPG file from the non-corrected RAW file. (If these have been made available in your camera's version of CHDK.) Or, come to think of it, would this also apply the distortion corrections to it as well? If so, then if the camera is set to a different zoom-setting when using RAW Develop, then that amount of distortion correction for that focal-length would be applied, would it not? If both are true, then just find whatever zoom-setting applies the least amount of distortion correction and set your camera to that before using RAW Develop.
Could an option be included in CHDK to save both RAW and DNG? Slow as it might be. Then all these options would be available from one shot.