problem with input block and also replace_block question

Your Random Source block has a very low sample time. By default the DSP Builder blocks will have a sample time of 1. If you want to make their sample time smaller, then drop a clock block into the design and set its sample time. You may then need to specify a clock on your DSP Builder input and constant blocks.

In addition I think 3 fractional bits is probably insufficient to sample your signal. The smallest value you could sample with that would be 0.125, which may still be outside your input range.

To replace every simulink Product block with a DSP Builder Product block you want

replace_block('sys', 'Product', 'allblocks_alteradspbuilder2/Product', 'Product')

If you're not sure what the full name of a block is, then drop it into your design, click on it and type:

get(gcbh, 'ReferenceBlock')

Generally it will be allblocks_alteradspbuilder2/<blockname>. As the help for this command says, you cannot undo the effects of this command so make sure you save your design first.