I have messed around with sql2005 in sd4.5 and 5.x even if not supported I generraly get one of two different problems, that is solvable with workarounds:
1. The authentification model is different in sql2005, more options can be set therefore the create db user doesn't work. - Can go around this by manually create db user... 2. The differnce by CAPITAL and noncapital in querys... Strange this one.. Didn't know sql syntax where case sensitive, but for some reason this is the case with sql2005? Maybe some setting.. First symptom is that you can not connect becase the case has changed on the user name or something..
Don't know if it helps you, but recheck, dubbelcheck that case on user name for example havent changed...
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