Weird garrysmod crashes when trying to change BASS.StreamFileURL.

“heap_corruption” was only thing i got from minidump (i got only 1 from like 4 crashes so far).
Code is
[lua]
if !oldBASS then oldBASS=table.Copy(BASS) end

function BASS.StreamFileURL(u,a,c)
local function c2(s,e)
c(s,e)
end
print(u)
print(a)
print©
oldBASS.StreamFileURL(u,a,c2)
end
[/lua]
Playing any stream without this goes fine.
Any ideas why this happens? Checked for infinite loop - does not happen.