In many practical VCD files, the $dumpvars simply starts the value changes, and there is no matching $end. If this is the case, the parser dies when the first time record, say, #1234, is encountered, with a mysterious exception '1234'. One possible solution is to check for # in vcd_value_change. I can send you a proposed diff if you are interested (did not figure the way to attach it here).

Sincerely, Dima.