The inner loop is terribly wrong. It should be an if (counter divides by 3 or counter divides by 5) in the first place:
for (counter = 0; counter < 1000; counter ++)
while((counter % 3)|| (counter % 5)= 0)
And the printf call is missing a comma between arguments.
if (counter % 3 == 0 || counter % 5 == 0)
There are other problems that might bite you at some time. For example, why is only the last of the three globals initialized to 0? (Luckily for you globals are automatically zero-initialized.)