No.. it does not necessarily mean there is some sort of money trouble with the seller. A short sale is done when the homes value is less than what is currently owed on the home.  Many area's homes in the United States have decreased in value since they were purchase and continue to decline in value.

It doesn't always mean there is money trouble but everyone I have done the seller was having trouble carrying their debt load.  Upon evaluating their expenditures the big mortgage was what needed to go.  If there was equity in the home they could sell it and rent but if the mortgages are greater than the value they choose to do a short sale.  The lender gets less money than what was owed but the lender does not lose as much as if they had to do a foreclosure on the property.  I know people that owe more than the house is worth but they can afford their mortgage and want to stay in their home. 

This is a big subject and every situation is unique.

Hope that answers your question

If you need sell the home and owe more then it is worth, a short sale causes way less damage then a foreclosure does.