I installed orange version 3 yesterday. I defined variables in excel file as per instruction given in documentation. When I used simple plots  it works fine but in case of classifier it's not working. Error message: data has no target variable. But I already set and saved the target variables. What will be the solution? Here is my data structure:ENZYME TYPE AGE GROUP   CONTROL 2 YEAR EXP  Relative increase in mean (in %)after 2 years of Exposure w.r.t control 4 YEAR EXP  Relative increase in mean (in %)after 4 years of Exposure w.r.t control 6 YEAR EXP  Relative increase in mean (in %)after 6 years of Exposure w.r.t control 8 YEAR EXP  Relative increase in mean (in %)after 8years of Exposure w.r.t control  10 YEAR EXP Relative increase in mean (in %)after 10 years of Exposure w.r.t controld   d   c   c   c   c   c   c   c   c   c   c   cclass   class                                           SGOT    19 TO 26 YEARS  24.12   34.03478261 41% 38.11818182 58% 39.88333333 65% 49.56666667 105%    50.7    110%SGOT    27 TO 34 YEARS  24.64   35.46666667 44% 38.25   55% 44.91428571 82% 49.7625 102%    50.88333333 107%SGOT    35 TO 42 YEARS  25.36   37.6    48% 39  54% 43.375  71% 53.36666667 110%    55  117%SGOT    43 TO 50 YEARS  28.9    37.76666667 31% 41.16666667 42% 44.7    55% 55.36666667 92% 56.96666667 97%SGOT    51 TO 58 YEARS  31.36   42.96666667 37% 41.36666667 32% 45.33333333 45% 58.25   86% 59.23333333 89%SGPT    19 TO 26 YEARS  21.8067 27.9826 28% 26.1909 20% 33.8222 55% 42  93% 34.2571 57%SGPT    27 TO 34 YEARS  21.04   34.2167 63% 28.975  38% 38  81% 43.075  105%    42.1833 100%SGPT    35 TO 42 YEARS  22.56   36.3    61% 40.9333 81% 39.825  77% 45.6667 102%    42.8    90%SGPT    43 TO 50 YEARS  23.58   42.8667 82% 42.7667 81% 40.5333 72% 46.3    96% 43.2333 83%SGPT    51 TO 58 YEARS  24.16   45.1333 87% 44.5333 84% 48.4333 100%    47.6433 97% 46.5    92%GGT 19 TO 26 YEARS  13.3967 27.6935 107%    32.6818 144%    40.2167 200%    33.9667 154%    33.8286 153%GGT 27 TO 34 YEARS  13.5    31.45   133%    41.225  205%    46.1429 242%    37.375  177%    37.2333 176%GGT 35 TO 42 YEARS  15.66   37.8333 142%    43.9667 181%    47.35   202%    45.6667 192%    37.5667 140%GGT 43 TO 50 YEARS  22.94   38.3667 67% 48.2    110%    47.9333 109%    46.4333 102%    39.7333 73%GGT 51 TO 58 YEARS  24  38.9667 62% 50.6667 111%    49.1667 105%    47.11   96% 40.0667 67%ALP 19 TO 26 YEARS  151.86  257.2587    69% 260.3727    71% 270.3722    78% 274.5333    81% 296.0571    95%ALP 27 TO 34 YEARS  152.46  218.75  43% 246.15  61% 257.0714    69% 273.1   79% 287.0667    88%ALP 35 TO 42 YEARS  153.58  235.9   54% 249.1333    62% 267.175 74% 276.9333    80% 300.6333    96%ALP 43 TO 50 YEARS  152.8   265.9333    74% 266.0333    74% 287.3333    88% 286.4667    87% 286.2667    87%ALP 51 TO 58 YEARS  153.14  235.0333    53% 254.9   66% 281.0667    84% 291.3767    90% 293 91%CPK 19 TO 26 YEARS  92.0667 109.0435    18% 148.3636    61% 146.3889    59% 141.1667    53% 157.4286    71%CPK 27 TO 34 YEARS  87.4    143.6667    64% 151.75  74% 147.5714    69% 164.25  88% 162.3333    86%CPK 35 TO 42 YEARS  96.4    149 55% 163.3333    69% 169.5   76% 173 79% 172.3333    79%CPK 43 TO 50 YEARS  93.6    173 85% 175.3333    87% 173 85% 177.6667    90% 181.3333    94%CPK 51 TO 58 YEARS  89  144.6667    63% 155.6667    75% 176.3333    98% 155.7767    75% 177 99%LDH 19 TO 26 YEARS  198.5   279.6957    41% 299.0455    51% 291.6667    47% 281.5   42% 296.5714    49%LDH 27 TO 34 YEARS  172.6   272.5   58% 296 71% 276 60% 265 54% 288.3333    67%LDH 35 TO 42 YEARS  137.4   246 79% 285.6667    108%    278 102%    283.3333    106%    306.3333    123%LDH 43 TO 50 YEARS  204.4   290.3333    42% 292.6667    43% 291.6667    43% 288.3333    41% 322.3333    58%LDH 51 TO 58 YEARS  138.2   262 90% 284.6667    106%    323 134%    375.6667    172%    324.6667    135%BCHE    19 TO 26 YEARS  25833.967   8313.7609   -68%    6551    -75%    6289.4444   -76%    5670    -78%    5042.7143   -80%BCHE    27 TO 34 YEARS  25271.8 10165.5 -60%    9682.25 -62%    7886.5714   -69%    6763.5  -73%    5960.5  -76%BCHE    35 TO 42 YEARS  23864.2 19860.6667  -17%    16186   -32%    15793   -34%    15402.3333  -35%    23498   -2%BCHE    43 TO 50 YEARS  21286   15834.6667  -26%    15279.6667  -28%    14917   -30%    14114.6667  -34%    13457   -37%BCHE    51 TO 58 YEARS  19063   9336.6667   -51%    6752    -65%    4395    -77%    2474    -87%    2258.6667   -88%
Target variable problem :- Classifier
data;orange