I'm having a similar problem with php 4.0.6: I have a DECIMAL column formatted DECIMAL(10,3) and all values (for example: 4,528, 3,213, 7,098) appear with only the integer part, a dot, and the number of decimals (4.3, 3.3, 7.3) after fetching the data with 'ibase_fetch_object()'. I've altered the column's definition so it has two or four decimals, and get the same results: the integer part of the value and a two or a four.
Has anyone had this problem, or know a fix?