Unable to FFT in place multiple times?

I’ve been facing an error when trying to do multiple FFTs in place using CUDA’s cuFFT API. Some sample code ahead that gives the same error I keep getting:

std::vector<Complex> host_signalx(N);
std::copy(host_signalx.begin(), host_signalx.end(), datablock);

checkCudaErrors(cufftXtMemcpy (plan_input, d_signalx, datablock,

checkCudaErrors(cufftXtExecDescriptorC2C(plan_input, d_signalx, d_signalx,
checkCudaErrors(cufftXtExecDescriptorC2C(plan_input, d_signalx, d_signalx,

The error:

CUDA error at test2.cu:235 code=3(CUFFT_INVALID_TYPE) "cufftXtExecDescriptorC2C(plan_input, d_signalx, d_signalx, CUFFT_INVERSE)" 

I’ve malloc’ed and it works when the FFT is computed once, but not twice- which stumps me, since I am looking to use it in a loop multiple times without having to free and allocate memory each time.

The error on the website is vague too, and says:

CUFFT_INVALID_TYPE   = 3,  //  No longer used

Any insights would be much appreciated.