Problem with Adaruit VCNL 4000 proximity Sensor Code freezes

I've the VCNL 4000 Proximity Sensor I use some sample code and at the very beginning

the following code hangs (never finishes)

readVCNLByte(0x81); is called
Can this problem be caused because the contact of the pin isn't very good.

I only but the part with pins in the sensor without to solder it.

Is it likely that this may be the problem ? I have not many experince with solder and the sensor is really small so i'd like to avoid it for first tests :wink:

Here the code. The last output in the Serial window is "pre product"

Serial.println("pre product");
uint8_t rev = read8(VCNL4000_PRODUCTID);
Serial.println("post product");
if ((rev & 0xF0) != 0x10) {
Serial.println("Sensor not found :(");
while (1);

If someone is hunting points at stackexchange i've the question also there: (hope double post is ok ? if not please tell me)