well it said you have $5.48 but only have $5.48 worth of points. Just wants to give you a heads up. Anyway I just withdrawed $5.47 and it worked. Here is a pic http://postimage.org/image/14lekpgzo/ sorry bad image host.
You don't have the full points needed for the extra cent. Probably like 0.10 points away or something. That's what I'm guessing, anyway.
It might be best to not round the number but to simply chop off after the second decimal place for withdraws. Of course you wouldn't set account funds to 0 in the database after withdraw but leave them (ex 0.0034213...) so that they still count to other funds when built up. Does that make sense?