Auto Correct in Word 2003

I do medical transcription for the ER of several hospitals - they just switched to a new system, NetLincScript (Chart Script), which attaches to my Word 2003. Instant Text Pro attaches just fine but with a few glitches. I did merge my auto correct but still use my spacebar for a few auto correct entries. One is "pat" for patient which expands into some long garbled medical phrase, another is "mg" which now expands to full word, "IV" does the same. I did check my "markers" to make sure that the spacebar was not checked. Any suggestions would be appreciated.