I can't find removeFileAtPath:error: method anywhere in the class reference of NSFileManager. It seems to be a very old instance method. There is a similar method removeFileAtPath:handler: that seems to be deprecated.
Try to use the removeItemAtPath:error: instead. From the class reference of NSFileManager:
removeItemAtPath:error:
Removes the file or directory at the specified path.
You should be familiar with the usage. I would suggest you to assign the error param to NSError variable so that you can check the NSError at the end of the operation, just in case:
NSError *error = nil;
BOOL deleted = [[NSFileManager defaultManager] removeItemAtPath:pdfPath error:&error];
if (!deleted) {
NSLog(@"Unable to delete pdf at %@, reason: %@", path, error);
}