SAGA/GDAL fails to open grid in QGIS 2.0.1 on OSX 10.6.8

Question

I want to try different grid/raster spline interpolation methods using SAGA in QGIS. I'm using the kyngchaos build 2.0.1-7 for Snow Leopard. Every SAGA algorithm I try gives the following in a popup:

Oooops! The following output layers could not be open
Grid: /var/folders/XH/XHXhaF3-Hp0EDNZQjtPjAU+++TI/-Tmp-/processing/50af3f2f86b2406db31f10014e9b80d6/USER_GRID.tif
The above files could not be opened, which probably indicates that they were not correctly produced by the executed algorithm
Checking the log information might help you see why those layers were not created as expected
This algorithm requires SAGA to be run. A test to check if SAGA is correctly installed and configured in your system has been performed, with the following result:
SAGA seems to be correctly installed and configured

The log says:

Algorithm Multilevel b-spline interpolation started
grid_spline "Multilevel B-Spline Interpolation" -SHAPES "/var/folders/XH/XHXhaF3-Hp0EDNZQjtPjAU+++TI/-Tmp-/processing/34f48cb284b54abe9179871ab766300b/leveling.shp" -FIELD "Z" -TARGET 0 -METHOD 0 -EPSILON 0.0001 -LEVEL_MAX 11 -USER_XMIN 657930.8638 -USER_XMAX 657896.114 -USER_YMIN 4530501.005 -USER_YMAX 4530453.77 -USER_SIZE 100 -USER_GRID "/var/folders/XH/XHXhaF3-Hp0EDNZQjtPjAU+++TI/-Tmp-/processing/USER_GRID.tif.sgrd"
io_gdal 1 -GRIDS "/var/folders/XH/XHXhaF3-Hp0EDNZQjtPjAU+++TI/-Tmp-/processing/USER_GRID.tif.sgrd" -FORMAT 4 -TYPE 0 -FILE "/var/folders/XH/XHXhaF3-Hp0EDNZQjtPjAU+++TI/-Tmp-/processing/46cc876ca93b4f7b8345e60455a0a2f2/USER_GRID.tif"
Error: executing module [Multilevel B-Spline Interpolation]
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library path: /Applications/QGIS.app/Contents/MacOS/lib/saga/libgrid_spline.dylib
library name: Grid - Spline Interpolation
module name : Multilevel B-Spline Interpolation
author : (c) 2006 by O.Conrad
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Load shapes: /var/folders/XH/XHXhaF3-Hp0EDNZQjtPjAU+++TI/-Tmp-/processing/34f48cb284b54abe9179871ab766300b/leveling.shp...




Parameters


Points: leveling
Attribute: Z
Target Grid: user defined
Method: without B-spline refinement
Threshold Error: 0.000100
Maximum Level: 11
Update View: no

Error: Grid file could not be opened.
Error: executing module [GDAL: Export Raster]
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library path: /Applications/QGIS.app/Contents/MacOS/lib/saga/libio_gdal.dylib
library name: Import/Export - GDAL/OGR
module name : GDAL: Export Raster
author : O.Conrad (c) 2007
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Load grid: /var/folders/XH/XHXhaF3-Hp0EDNZQjtPjAU+++TI/-Tmp-/processing/USER_GRID.tif.sgrd...
failed
GDAL: Export Raster: could not initialize data objects
Converting outputs
Loading resulting layers
Algorithm Multilevel b-spline interpolation finished

I used a tab delimited text file and also tried a shapefile, both containing only points which I have to have in CRS NAD 83 / UTM zone 18N EPSG:26918. Naming a new file for the parameter "Grid" gave similar results, and the parameter "Target Grid" has only one option, "[0] user defined". I tried reinstalling QGIS. I have 2.0.8 compatibility unchecked in "Options and Configuration", but I tried with it checked and restarted. It looks here like SEXTANTE used to let you choose a path for SAGA, but it appears that with Processing in 2.0.1 choosing a folder for SAGA is no longer an option. I found libio_gdal.dylib and libgrid_spline.dylib in /Applications/QGIS.app/Contents/MacOS/lib/saga, but I don't know what to do with them. Is the problem with SAGA or GDAL? I have GDAL 1.10.1. What should I do to get SAGA algorithms working in QGIS for OSX 10.6.8? Thanks!

BTW, here is my data. I used the Z field for interpolating.

X   Y   Z   Labels
657946.114  4530468.710 53.250  Curb
657900.751  4530477.953 56.405  Station
657900.020  4530469.788 55.935  Ref Elev
657891.472  4530451.005 55.691  Pine Tree
657904.272  4530452.899 55.025  10 m down sidewalk
657915.404  4530459.198 54.502  20 m down sidewalk
657922.472  4530463.302 54.228  30 m down sidewalk
657932.883  4530468.129 53.730  40 m down sidewalk
657940.599  4530474.466 53.230  50 m down sidewalk
657927.419  4530482.176 53.976  Statue
657917.784  4530475.559 54.494  10 m from statue
657909.383  4530469.617 55.074  20 m from statue
657897.869  4530461.605 55.840  30 m from statue
657890.491  4530457.816 55.974  40 m from statue
657919.176  4530486.939 54.180  Halfway 1
657911.217  4530480.177 54.989  Halfway 2
657901.213  4530472.673 55.963  Halfway 3
657890.839  4530465.266 56.741  Halfway 4
657886.289  4530469.603 57.389  South Corner Court
657895.552  4530477.862 57.007  10 m SCC to BT
657903.860  4530485.648 55.837  20 m SCC to BT
657910.264  4530489.290 54.853  Birch Tree
657894.773  4530485.335 57.377  North Corner Court
657898.042  4530491.892 56.567  Between NCC & Black oak
657880.864  4530498.486 57.664  2nd Light
657883.579  4530500.242 57.113  10 m off 2L
657885.741  4530503.770 56.276  Gully off 2L
657896.024  4530498.490 56.084  White Rock
657945.532  4530467.694 53.413  Close