Time series graph issue


I am using AFNI to look at a dataset containing peak activation times of virtual sensors from MEG data that has been compiled into clusters using MNE and then transformed to SUMA peaks. We use 3dSurf2Vol to create clusters and their peak times in nifti format and then expand it into the volume using @ROI_modal_grow. The output file that I am trying to extract the time series graphs for is our cluster peak times nifti but when I attempt to visualize the voxelwise time series with this data as the underlay I get the following error: "Can't draw graphs for this dataset: Num <2". Is there any way to manipulate the file or the AFNI gui to create parameters to allow the visualization of the time series? Thank you so much!